That was a pretty complete list of why stone weapons have problems ... I'll go over it again and regroup it:
1. Wood is generally at least as hard, if not harder to maintain than steel. It draws moisture and is harder to dry. It rots. It splinters when hit with other weapons. None of these points are critical, but they certainly do not encourage the use of wood bodies on weapons.
2. Stone is inconvenient to sharpen, and breaks, chips, or dulls badly. Stones must be replaced constantly.
3. It is also irregularly shaped, transfers shock strangely, and is inconvenient to mount in a handle (of any design). This usually results in the handles or wood bodies of stone weapons being heavier than should be necessary, in order to keep the blades in place. The irregular shapes also tend to wear the handle and/or cut the bindings, unless the stone is VERY carefully shaped. Related to this, stone blades are severely limited in size (you can only get a stone blade about six inches long, max), which creates more mounting and binding problems.
4. It takes a lot of time and effort to get a good sharp stone weapon. Added to #2 above, this creates a logistics issue.
Now, I have made a few of these, and a lot of other people have made a lot more, and everyone I have ever seen testing a stone weapon has come to this set of conclusions. None of these issues are immediately fatal (i.e. a stone weapon does "work" in the most basic sense), but each is a big enough problem that most people are going to want to go to metals at first opportunity.
Riptokus, by your own statements, you have never made or tested a stone weapon or tool of any design, and you have never handled a real sword. Test these things, and tell me if I'm wrong. You're talking to a bunch of people who are swordsmen (myself, Guspav, half the people on this board), trying to tell them how a sword works. Don't make a conjecture based on nothing... ("but it killed a horse", as if horses are immune to attacks by steel two-handed swords). Come up with good test results to demonstrate your point. Because about a hundred million historians, re-enactors, and hobby weaponsmiths disagree with you... they all seem to think people generally go to metal blades at first opportunity, and for a number of very sound reasons. Therefore you must prove your point, as it goes against accepted logic.
I get my information from purly local sources, people who use swords locally. This is why I am trying to pin down your claims on the Macuahuitl being inferior. I am now planning to build one based on the following information, to hand to my sword-using friends. Lacking a real Macuahuitl or the real details of construction, It won't be accurate.
Obsidian obtained from South Central Colorado
Oak 2x4 if available at the local hardware store, if not, some other hardwood if available, if not, cedar, then pine.
Some Hemp Twine.
Based on the description here-http://en.wikipedia.org/wiki/Macuahuitl
I will then cut a handle out of the wood equalling about 1/5th the length. This will be wrapped with the Hemp twine for grip. Knowing nothing about the properties of a good handle, I will taper it similar to a club and wrap the twine to make it comforable in my hand.
I plan to carve blade places out for the blades, relatively uniform. They will be an inverted wedge, since with my method of attachment, that will probably hold the blades in best. I am then going to get chewing gum, chew it into a set thickness, and attach 10 blades to each side using the chewing gum, filling the wedge completly. I then plan to go to several people around me who use swords and have them tell me how shittily of a job I did, since I have never made a sword in my life before and expect it to be complete crap.
With this weapon though, I expect to debunk the following thoughts
2) The blades inside the wood would jump around on impacts, and damage the wood holding it together (Stone is inconvenient to sharpen, and breaks, chips, or dulls badly is debunked by the stone used, obsidian, which last I checked, was famous for breaking sharp)
3) The Stone weapons weigh more then steel weapons (I didn't quite understand what you were saying with your addition, but I suspect that either I will debunk it or prove that with experience manufacturing this weapon I COULD debunk it.)
4) The Stone weapons aren't as well balanced as the Steel weapons. (and take alot of time to create and keep sharp)
5) The parts that wear out on a stone weapon would wear out too fast to be worth it when compared to the speed of sharping a steel weapon(Rope, Bindings, Blades)
Lacking any comparable material that the Mesoamericans had to properly treat and seal their wood, I will be unable to debunk the rot to your satisfaction. My experence with carpentry gives me hundreds of modern methods to do so, almost all of them possible by ancient people in some form, but my ability to prove that they were used is nil. http://en.wikipedia.org/wiki/Pressure_treated_wood#History
Gives you an idea on some of the methods used today by us. I suspect the Mesoamerican method would have been a combination between the selection of wood and soaking it in a particular kind of oil prior to use. Since they were picked up and carried, I doubt it was common practice to allow them to sit idly next to a ant's nest, which would be common with houses, or use them as shelter against the elements, such as doors, therefore they would be likely to last awhile without extensive treatments, with their main requirement being they don't get destroyed if a little rain falls on them. Without you having a greater understanding of wood, the only way I can really prove point 1 is by stating that this is made of wood-http://www.powerhousemuseum.com/collection/database/?irn=173811
400 years, I don't know any warrior who would need a weapon for that long. BUT IT'S A CHAIR! How long would a Macuahuitl need to last for it to be worth it to produce them? My estimate is that if a Macuahuitl lasts 10 years with no significant degradation, it would be just fine. Swords don't have to be Heirlooms to be effective in combat. I believe that a wood Macuahuitl wouldn't be threatened by rot, if manufactured correctly, for at least a timeframe measured in the years. A little water falling on it, or not wiping off the blood, wouldn't hurt it as bad as doing that with steel would, I believe. But since I don't know the processes, I can't build an exact replica, so I can't test the ability for it to weather the weather.
I suspect that the Macuahuitl I make will be both acceptably light enough to be usable, Balanced enough to be usable, and easy to maintain. I suspect that with just a small bag, I will be able to quickly replace broken blades, if necessary. I also suspect that my attachment method will prevent the stone from jumping around and damaging the wood. I strongly suspect that even with my crude manufacture of the weapon, It will preform beyond your expectations. I also suspect that a real Mesoamercian Weaponmaker could make something on par with the stuff that came from Europe. However, not having access to a real form of this weapon, we will never know for sure. The point of this isn't to prove definitly, it is just to prove enough to pass the point of "acceptable plausibility". Enough for you to agree that yes, more factors then technology level were involved with the rejection of the Macuahuitl. For no examples to remain means there was a pretty through war declared against this piece of equipment. This is keeping with the Spanish philosophy of the time of burn the culture to the ground, so ours may take better root.
Which would be faster to make, given the creator has roughly equal experiance with both processes and has all the materials? Assuming better than poor quality, but not masterpiece. Also, how long does it take to become skilled enough to make decent quality macuahuatls versus swords? Also, would the Mexias (A) Have knowledge of iron deposits and (B) how to extract and refine?
Another question is, was there another European country that would have had the ability and benefitted from a trade relationship with the natives had they lasted against the Spanish?
Later in history, there were quite a bit of examples of Europeans allying with local natives against the other powers. Trade was also something they all liked. Natives had a lot of gold, Europeans had a lot of Trinkets. Gold was more useless to natives then trinkets, and it was the opposite for Europeans, so typically they both thought they cheated the other. This makes for a great trade relationship, so no doubt there would be extensive trade. As for weapon manufacture, Mesoamerican Macuahuitls would be more prone to be able to be manufactured assembly line style. Think of a Macuahuitl like a disposable razor. You have the handle, you just have to go out and buy the blades. Since different stones have different densities, fitting the right stone in the right slot determines how effective your weapon will be, as well as balance and everything of that nature. Macuahuitls seem to me to be very customizable, but Ron's got a serious point here. Obsidian blades will wear out significantly quicker then iron swords. I suspect that Iron swords are harder to manufacture on an individual level, but just like the disposable razor, you gotta keep buying the blades!
I wasn't aware that the Celts were so much closer in technology levels at the start of empires on Europe then the northern tribes at the start of Empires in the Americas. The Mesoamericans had extensive things going on for them that more northern tribes hadn't even thought could exist. The results of Divergent Evolution were most pronounced in Central America. This is where corn came about, an invention that was unmatched in the rest of the world. There was more in Central America and Western South America that already worked then in the rest of the Americas, therefore if any place retained technology, these places would. Unfortunately, This part of the world was the part that met the Europeans first, and they had the misfortune of meeting the Spanish. The Spanish were fresh out of wars of extreme hatred and religious intolerance, and had developed a practice of burning the culture currently there to prevent the other side from easily taking the place back. They razed the Empires of Central America to the ground, and salted the earth of the technological marvels that came from there. The Maya developed a calendar which is much more accurate then what we have. We never adopted it, partially because of it's "pagan" roots, but mostly because we already have one. That doesn't make it primitive or junk, it is just something that would fill a role we already have filled, and the Maya culture was demonized early enough that we could go around that piece of equipment that worked better then ours.