You need to learn the difference between marginal tax rates and effective tax rates. That and basic economics.
I do know the difference and even supposing you modeled the Capital Gains tax after the Progressive Tax we use for income, you'd still be nowhere near the absurdity of 90%.
What happens when we have a high marginal tax rate? High tax rates do not stifle corporate growth. They stimulate it. How you ask? Instead of paying CEO's 10's or 100's of millions, corporations reinvest it in the workers and capital projects.
So you're saying the government won't tax a CEO that reinvests the money in the company but would tax him if he kept the earnings for himself? If so, that's not even remotely true since corporations are taxed as if they are people.
The purpose of government is not to allow and justify that some people make unlimited income. Corporate America was much more stable and the middle class much stronger with higher tax rates.
Stronger government, perhaps, since government can only exist from the capital the private economy can produce.
You are spouting right wing propaganda that the modern robber barons are feeding you.
Then by contrast are you spouting left wing propaganda from the modern socialists and communists?
"Reason obeys itself; and ignorance submits to whatever is dictated to it" -- Thomas Paine