What made mesa central the most popular part of Mexico?

Answer 1

It has a temperate climate, plenty of rain and rich soils. This has contributed to increased agriculture and higher population density. Nowadays, the Mexican Central Plateau is the most populated region in the country.

Answer 2

Because the Mexican Central Plateau has the most comfortable temperatures in Mexico, as the northwestern areas are dominated by the Chihuahuan and Sonoran deserts, and the southeastern regions are composed by tropical rainforests:

Towns and cities on the Mexican Altiplano, as well as those found along the Sierra Madre mountain ranges bellow the 1,000 meter mark (3,300 feet) have relatively constant, pleasant temperatures throughout the year between 16°C (61°F) and 20°C (68°F); the most common climate is subtropical highland. On the other hand, more northerly locations experience sizable seasonal variations. Above 2,000 meters (6,600 feet), temperatures drop as low as an average yearly range between 8°C (47°F) and 12°C (54°F). Parts of the northern altiplano and high peaks in the Sierra Madre Occidental and the Sierra Madre Oriental occasionally receive significant snowfalls.