The discussion is about marginal tax rates without stating it as such. He might not have been OK with a 95% MTR, but would he have done it with a 45? a 50? People could opine on what he would have or would not have done given that, but I think it's reasonable to say that many people would, and do (given that successful innovators and businesses exist in higher tax countries.) Higher marginal tax rates don't mean you don't get rich; they mean you don't get quite as rich, which is what much of the proposals are about.