Once again, generalizations are never good. Not every pilot in Mexico is well connected and because of that the government tailors the law to them. If that were the case their connections could've brought the government into the bankruptcy process to keep Mexicana operating (the pilot union asked for that on numerous occasions, Calderon said the government would not step in).
The law requiring Mexican Citizenship to hold anything higher than a PPL in Mexico stems from the close proximity to the US. In the early days of commercial aviation there was more availability of US pilots to fly the aircraft in the emerging aviation business in Mexico (Charles Lindbergh flew for Mexicana). Mexicana was owned by Americans and the planes were flown by Americans. These laws came as a result of that years later.
Protecting jobs in your country is not a new thing. Some countries have laws others do it in more subtle ways (airline policy, pilot union rules, language requirements, license requirements etc). Airlines like TACA require Central American Citizenship. I understand Brazil has a similar rule to Mexico. Reciprocity would only exist as a result of demand. If tomorrow Mexican airlines have to ground planes due to pilot shortages the law would be changed. The same would happen anywhere else.