Sure enough, they will invest it, because we are speaking of marginal incomes of the rich that could be taxed away and spent by government - these people already consume everything they want, the only thing they do with extra cash, is investing it.
There are already more than enough available investment dollars in the USA. More of them than viable business ideas. Adding even more means only asset inflation and even higher P/Es that progressively make stock market resemble a Ponzi scheme, and further increase of real estate prices that are already unaffordable in most of the country.
