I understood your argument. It's just not how it works. Even if amassed wealth was used to buy stuff as a exchange of goods, it wouldn't be anything significant, and it would be less significant the more wealth we're talking about. That in itself should clue you in on why this doesn't work.
If taxes is a problem in terms of inequality, why... not tax it more progressively then? That's the whole point of it. Reduce taxes for lower brackets, increase for higher brackets. Even if you thought 0% tax makes sense, which sort of already exists for the lowest bracket, and you want this to apply to more people... then, just do that, starting at from lower income side. Do the same starting from the upper income side, but there you increase it significantly. How far you go, is politics.
Put into place stricter regulations for the exploitation of workers. Actually enforce this stuff, not just give fines that are less than the gains. Replace your election system, it's broken. Etc. There are soooo many things, that actually make sense, and would have a good effect. But looking at say 400k+ incomes and thinking "tax it at 0%". Reagan's grave would look like the classic zombie stereotype, except it would be his dick protruding from the ground.