Mexico has some additional advantages beyond its lower costs, somewhat more equatorial position, and greatly reduced liability risks: soft money political campaign contributions were banned in 1996:

http://www.ife.org.mx/wwwife/reform2.htm#3condi

Not only is there no NASA or anything comparable in Mexico (just like in Australia), there also aren't nearly as many ways for entities like Boeing & Lockheed to LEGALLY subvert the emergence of potential new competitors such as Scaled. And Mexicans are already catching on to how corrupt NASA and the other bureaucrats and government contractors are, as this recent article in Mexico's most widely-read political magazine helps demonstrate:

http://www.proceso.com.mx/home_exclusivas.html?eid=2618