Mexico's Dropout Economy: Many Students Quit After Sixth Grade to Help Their Families By Kevin Sullivan and Mary Jordan suggests one reason for Mexican poverty:

A generation ago, Mexico and South Korea ranked near the bottom in academic achievement among the 30 nations of the Organization for Economic Cooperation and Development, said OECD official Andreas Schleicher. Today, among people age 25 to 34, Mexico ranks last in the same OECD studies, while South Korea has risen to No. 1. South Korea's highly skilled workers produce some of the world's most popular cars and electronics, but Mexico's workforce still relies largely on sweat.

"It's not that Mexico has declined, it's just that everyone else has progressed," Schleicher said. He said one explanation for the stagnation is clear: Public education is nearly a religion in South Korea, while Mexico ranks last among OECD countries in investment in primary education. "Mexico and other countries that have not kept pace with everyone else in education have paid a heavy price, economically and socially."