My Opinion about How the Mayan Civilization Disappeared

My opinion of how the Mayans collapsed is that the environmental problems and rapid rise of the population caused the Mayans to suffer from terrible malnutrition and diseases and invasions, and I concluded so because after analyzing the various clues from the website http://www.learner.org/interactives/collapse/copan/monuments.
php?s_id=69374873779EDADCBCDE, I found evidences that leads up to this conclusion. For example, the website shows that the 80% of the Mayans' bones that were discovered suffered from Anemia, because they had a very spongy appearance. Anemia is a disease that is caused by lack of red blood cells and iron, which is often resulted from malnutrition. This evidence leads up to my opinion because Anemia's cause, malnutrition, is probably caused by a draught or any other dangerous weather that killed most of the Maize, the Mayan's major crop. Also, malnutrition could be caused by rapidly rising population of the Mayans. The website gives a clue about erosion of the soil, probably caused by overfarming. Tremendous amounts of obsidian Mayan blades also give a hint of how populated the Mayan town was. I'm sure that high population density would've caused lack of food, resulting in overfarming. But while overfarming, Mayans probably couldn't have used the concept of fallow land. Fallow land is a land just left unused after harvesting so the land will fill up with nutritions again. But Mayan farmers had a vast city to feed; they could not leave the land unused if they want to produce enough crop for them to survive. All these evidence gives us a hint that suddenly, Mayan's climate changed, no existence of fallow land decreased the amount of crop production, an epidemic struck, and people died out in rapid speed since to Mayans, food was an important issue. But lack of food or epidemic proabably wasn't enough to collapse a gigantic civilization; this is why I think that Toltecs probably did their part of destroying the Mayan civilization. There is a passage in the website that says that the monumental altar in Copan that Mayans started buildig were unfinished. Lack of food and an epidemic probably did not stop the Mayans that survived from creating an monument. This might be an evidence that Mayans were "forced" to not be able to finish the altar, and the greatly weakened civilization could've been trampled by the footsteps of Toltec. Even though nobody knows for sure how the Maya civilization disintegrated, but I have an opinion that is supported by various evidences that the Mayans probably all died out from lack of food and a deadly epidemic, and those who survived were killed by the invaders.

This is few of the numerous obsidian blades discovered in Copan ruins.

This is the unfinished side of the monument in Copan.

This bone shows that this Mayan person suffered from Anemia.

This is the city of Copan, where the evidences of the websites are discovered.