Well it's really based in a class structure that goes back to Colonial times in Mexico and Latin America. The "ruling classes" can trace their power back to Spanish appointments and land grants, despite a buncha revolutions to stop that.
Mexico has the elements needed to step up into an industrialized nation. Natural resources, industry potential and a work force. But the fact is that Mexican business leaders and goverment officials who generally come from the Upper Strata tend to control all the money and use poverty to control the Pobre's. Add that to the fact that forgien business use Mexico and the current pay rate of Mexico (about 50.00 bucks a week) to increase profit margins while making sure that the Jefe's get their cut it causes a vicious circle. I'm not trying to sound socialist revoluntionary, but thats how it is.
The goverment workers Police, Postal, Fire, etc are all considered low level menial jobs and there for paid low and not given to the best and brighest or people that have a committment to service. It could be fixed but not quickly. At least Calderon is making a little headway.