I think this could be brilliant. The key is his desire to see people invest and recirculate that money. Taxing at 100% above a certain level is your incentive to donate to charity, put your money into investments, etc.
If you make 500k and you're afraid the the government is gonna swipe all that, you dump the remaining 140k over the cap into investments- your money is going to something good, is still directly beneficial to yourself, and everyone wins. No disincentive, unless you're a greedy asshole that just likes to sit on cash.
such an oversimplification. Its a terrible idea.