Motorola tried that not too long ago. Didn't go well. If you want to decimate American wages, you could do it, but if you at the same time deport people who were the most ready to work for a pittance, it's going to be hard to do this without riots. Then again, Stephen Miller wants those riots, so maybe you're right.
The crux of the matter is that those workers won't be able to afford the iPhones they're assembling, however.