What is the trend for all Hispanics?
http://www.pewhispanic.org/2015/09/15/the-impact-of-slowing-...
Mexico specifically appears to have finally hit an economic level of opportunity where people wanting to leave to the US has slowed down significantly. However, the rest of Latin America isn't doing nearly as well as Mexico. Mexico's GDP per capita is now above Russia, Brazil, Turkey; and their unemployment rate is at 3.8% (4.4% urban). China's manufacturing labor costs are now above Mexico's; that will continue to increase US manufacturing shifting some things away from China and to Mexico, bolstering their economic performance.
Language is a barrier, though. PR is a barrier. The business culture is more Wall Street or Bourbon Street than Sand Hill Road. Still, it's a great place to come to.
China's wages and taxes are both still lower, but Mexico is enormously less corrupt and your trade secrets won't get stolen. It's a whole lot easier and cheaper to start a business as an outsider and dispute resolution isn't quite so insanely biased.