"When it was their turn" is an interesting concept. Since the Maya had no trade or diplomatic relations with European powers before they met them in battle, they were as much caught off guard as the Mexia. A better example is still the natives of the current United States, who did have long-standing trade relations with European powers and therefore adequate time to get their hands on steel equipment
Actually, no, it is a bad comparison. The Natives of the United States had weapon technology significantly less then the empires further south. This would be more like comparing the engineering of the Roman Legions and the Celtic Tribes around AD 43. Sure, you can do it, but really what does it show except that relatively close areas don't always have the same technological level?
As for guns, this is an example of what I am stating. Guns weren't adopted right away because the combat role was already filled by bows, and the advantages of the early gun couldn't compete with the entrenched concept of the bow combined with the effectiveness. There's quite a bit more I can state on the subject, but I can easily concede that north American tribes didn't adopt guns right away because of lack of effectiveness. I'll bet all the tea in China and Tibet that the Cherokee adopted European cannons quicker then they adopted extensive guns though. Not knowing anything about Cherokee military history, I can't be sure. Artillery didn't exist in the Native arsenal because siege warfare was still very primitive on the continent at the time.
As for Adoption of the weapons by the Tlaxcala, the image the lienzo de tlaxcala was supposedly a picture of the Tlaxcala well after the conquest. This image was also done significantly later and with spanish supervison.
And despite what you think, there is no doubt there was significant European contact with the maya in situations where the Maya weren't caught off guard. 1527 was the first attempt at conquest by Francisco de Montejo, He was defeated but returned in 1531. In 1540 his son took over. When the Xiu Maya converted to Christianity it allowed a solid enough road by the Spanish to finish off the majority (but still not the totality until late 1600s). Just because the fall of the Maya isn't as popular doesn't mean there wasn't significant conflict there. There was probably more fighting involved there then the rest of Central America, though a lot less is known.
I can get into quite a bit more detail about the wood. Let's just leave it at your "I did some carpentry growing up" doesn't quite trump my "I do carpentry as a profession", and leave it at maybe MR. Riptokus knows what he's talking about this time at least eh?
Having maintained both a 9mm Colt, a M16A2, and a M240G in the hot, humid jungles of northern Oahu, Hawaii, I might know something about maintaining steel weapons in jungles. Granted, these were usually only for 5 or so days at a time, but these were in situations much more similar to what the spanish soldiers and what native warriors would be in then what you have probably done (not knowing for sure, I leave that open. I'm not discussing this with your brother. For all I know, he might have a different opinion on the situation)
Let me make it clear, it is a non-stop issue. You are resting for a minute? Pop out the oil and quickly apply a light coat. Check your cloth, make sure it's not contaminated with water. Forgot to do it at the last stop? Enjoy your rust spot. It will grow if you don't eliminate it, regardless of the usage of oil. Stopped for the night? Check the hard to reach spots. Sure, you've got to be more OCD with a gun about it then a sword, but still.
Bottom line? I don't see higher technology levels of the natives equaling a sure increase of European metal weapons. I can see that it IS possible, but it's not a sure thing. There is more to the question then "technology", such as contact with European culture, and whether or not those weapons are seen to be on par by the warriors who use it. I still strongly disagree with your statement that a Macuahuitl is a clumsy weapon and that iron is superior. Even you must admit that Obsidian has a better edge then steel, so as long as a Macuahuitl has balance and control equal with a steel sword, then it can be said that a Macuahuitl is on par, if not better, then Spanish Swords. That leads logically to, Steel weapons wouldn't be adopted of and by themselves. That isn't to say that outside forces couldn't change this, such as the Spanish insisting they abandon the "pagan" weapon they used to use which served such an important religious role. The more the Macuahuitl played into religion, the more likely the spanish would attack it purely for that merit. Remember, the Spanish are the ones that burned all the "works of the devil", and the lack of an intact weapon of that sort is odd, considering there is quite a bit of junk from even older then those times found in areas that the Spanish didn't "Christianize" so throughly. If that weapon itsself was seen as a symbol of the region, think of what would have happened? Also in the before mentioned lienzo de tlaxcala, there is an image of books, costumes, weapons, idols, and a bunch of other things being burned. The loss of heritage is horrific, and hinders our ability to truly learn from history. THAT is why book burnings are so wrong. You may create a moral justification for your world view for 500 years, but every civilization eventually falls, and the next one that comes is lesser then it could have been had you not destroyed a way simply because it was different then yours.
*Edit- Forgive the rather odd statements that might be in there where the correct word wasn't used quite right (like stopped for the knight. There, fixed that one. Damned if I know what I was high on, it's bedtime, goodknight!