Give Trump time. He's only had a week. I'm sure by the time he's done no one will look to the US as their first choice. Most of the world is appalled by his behaviour. Perhaps some of the world's "best and brightest" will still be lured by the money but I would think many of them will consider more rational nations. 

I could even imagine companies run by enlightened individuals like Apple, Google, Tesla and the like would consider moving headquarters to Canada or Europe.