When we were helping to rebuild Germany and Japan we should have had a Marshall Plan in place to build up Mexico and Central America too. I think that was one of our big blunders over the past few decades from a foreign policy standpoint. Mexico is rich in natural resources, and has the potential to be a very rich country, but like any nation that has a Spanish heritage, it’s a freaking mess politically. The United States and North America as a whole would be in far better shape with an economically viable and politically stable Mexico.
The whole system in Mexico is such a disaster I don’t think we could have helped them. They have a caste system with very rich light skinned (Spanish descendants) at the top of power and money, the darker the skin the lower they are on the rung. The rich do not want a middle class, they want no way for those at the bottom to work their way up. The only way up in their system is through criminal activities. It is just a mess. They do have resources, and possibly if we had not let their poor migrate in mass numbers at some point they might have had a revolution and ended up better off. Mexico has had many revolutions with no real improvement though so who knows. No way to know but I think we were better off to keep out of that mess, we should have secured our borders and enforced our laws.
When we enforced our immigration laws Mexican men came up here and worked agriculture jobs legally, but they were temporary/seasonal jobs. I know of several that went back and forth and used the money earned here to build a business in Mexico. When we stopped enforcing our laws most stopped going back and brought their families up here. It is our fault we decided we would allow our politicians to ignore the laws.
If we had stuck with enforcement I think Mexico would have gradually changed with the workers going back to invest their money in business. It was headed in the right direction.