Living in Mexico, I share most of the things you have said. Mexico can’t be compared to the US in wealth, crime rates (although one should compare individual cities) and most of all baseball fandom. If I had to bet I would say it´s impossible that a MLB team establishes down here. However, there are some things that could happen:
1. Manfred has talked about the possibility:
http://m.mlb.com/news/article/232063444/rob-manfred-wants-mlb-games-in-mexico/
https://www.cbssports.com/mlb/news/mlb-sounds-serious-about-expansion-into-mexico-for-regular-season-games-soon/
2. As said Mexico´s population (around 130 million), with a lot of wealthy people amidst a shameful poverty, could embrace the team as a "national team", like the soccer "selección". Besides, there is a lot of people who follow baseball on a regular basis and will like to see their team in a Mexican city, not having to go to the States for it. And remember we also have wealthy pink hats that like to show up in sporting events all over the world.
3. There are 15 Mexicans with more than 1,000 million dollars (TV Azteca´s Ricardo Salinas, 3600 and Televisa’s, Emilio Azcarraga 2100). The richest, Carlos Slim, 54,500 million dollars is a big baseball fan (grrr MFY fan) who attends MLB games frequently and who would get TV for Telmex (his biggest company) in the near future.. Alfredo Harp (1200) is the owner of Diablos Rojos in Mexico City. There are a lot other wealthy Mexicans that love baseball and could see a good business investing on it.
4. Mexican-Americans in the US are more than 36 million. Wouldn´t some cable network in the US see a good business in transmitting the games sponsored by tacos, cerveza, tequila, etc.
5. Well, maybe big stars born in the US wouldn´t like to come, but what about all latinos that are playing in MLB baseball. The language and many of their habits are the same. Indeed, American young players play in many of the winter leagues in Latin-America. American rookies will accept contracts and of course when they hit free agency they won´t sign here, but Dominican, Venezuelan and Puerto Rican players will sign if the dollars are OK, which could be.
6. Between politicians baseball is quite popular: the front running candidate for México´s next year presidency López Obrador loves baseball and in spite of his age (63), he plays baseball as frequently as he can. Other politicians (the president of the Bank of Mexico, the Treasury Secretary and one of the Senate leaders, engage in baseball games). All of this is to say that customs will be no problem, and the government will support baseball because of the welfare it will bring; the same it has supported all the American industries (car, electronics, etc). Maybe Trump would be the one who doesn´t like it and will want a very high green monster.
In conclusion I think it is possible, but I wouldn´t bet on it.