A 100% income tax means there's no incentive to remove profits from a business beyond that income, since you can't spend any of it, so it will just encourage increased accounting trickery to justify "business expenses" for things like purchasing private islands, sports cars, and luxury vacations.

80% is high enough; for every $10 million they withdraw for personal spending, they keep 2, and the other $8 million would go to pay for the services requested to run the rest of the country that enables them to produce their wealth. (Including all their employees and customers.)

Then we still benefit from the efficiencies inherent in the profit motive while having the ultra wealthy pay their fair share.