The main reason the Maya died out was because of wrapping their heads and anemia, from being malnourished, and not getting enough iron in there diet. 80 percent of the Mayans were malnourished, which is alot, and that would probably be enough to destroy alot of the empire. The Mayan's also bound the heads at birth so that they would look "pleasing", but that could also cause brain defects, and that could have made their society alot more vulnerable, and easier to be taken over. Although the main reason was mostly related to the people, there are still other things that added to the collapse of the Maya.
Mayan skull with anemia
Mayan skull