Why doesn't Major League Baseball open a franchise in Mexico City?

Larry James offered a marvelous list of questions about immigration that I referenced on Grits for Breakfast. One of the most provocative : Why doesn't Major League Baseball open a franchise in Mexico City?

Why indeed? What a brilliant idea. I think it'd make a ton of money. Here are some reasons why:

• Baseball has a long history in Mexico and a built-in natural fan base. The Mexican League has 16 teams, whose fan base could be mined and marketed to nationwide.
• Mexico City could fill a big stadium. It has 20+ million people, as big as any US market, and as the first Mexican MLB team it would draw fans from nationwide.
• Millions of Mexican immigrants and first-generation citizens of Mexican descent in the United States offer continent-wide subsidiary merchandising opportunities.
• Baseball players would still cost millions of dollars, but labor costs for everything else from building or modifying a stadium to mopping the bathroom stalls would be cheaper in Mexico. That would improve margins every year.
  

There are probably other reasons for and against, but that strikes me as a workable idea. Now all I need is a couple hundred million dollars or so to get the plan rolling, and we're in business!