It's a mixed blessing. The deal is very similar to remittance basis taxation which we had in the UK until recently. It probably benefited the country in the way you say but was also kind of unfair in that foreign billionaires living here got a much better deal than British ones. It was just scrapped and a lot of millionaires are leaving for better or worse.

I'm skeptical that Trump will manage to get the tax changes through the house and senate and that they would remain through the next government which might put people off dropping $5m on the thing.

Also would Musk who has three citizenships be able to drop the US one and get a gold visa?