Why do you think the factories are not here now???
Are you joking? The standard of living in Mexico is terrible. The average household makes $10,000 a year. The average in the U.S. is over $80,000. In what world do you think paying 8 times more than before is going to lower prices?!
Maybe you just decided to not read Post # 11, is that it ? In what world do you think shipping from Oaxaca to Cleveland, is cheaper than from Detroit to Cleveland ? Guess what, GM has already moved from Mexico to Detroit, and that was before the corporate tax, regulations$$, and energy costs went down in the US.
Lastly, for now, Mexico has not gotten hit with the tariffs. Not yet.

Keep watching.
The cost of making a car would skyrocket, but you think they’ll make that up with shipping costs?!
And GM has plants all over the planet, including several in Mexico.
1. And some have left Mexico and returned to the US already. 1800 GM jobs came back from Mexico - to Texas. 1400 Ford from Mexico to Michigan. 1400 more Ford jobs from Mexico to Kentucky.
2. Making it up In shipping costs + the other things I mentioned, and I forgot to mention robotics. Cheaper to make stuff with robots here, than with Mexican workers.
GM, Ford, Chrysler made cars in the US for decades, before ever setting foot in Mexico. Things are going back to how they used to be. Keep watching.
Lots of other manufacture companies coming back too. Don't just take my word for it. CEO Jeff Immelt of GE has said the U.S., on a relative basis, has never been more competitive. For instance, he’s said it takes three hours or less to make a refrigerator, so the total cost can be lower to have it made domestically, versus in China or Mexico, when factoring in other costs including transportation.