If you've gone public with the company yes, you've set up the situation where paying your due means giving up some control of the company. That was a you decision. But congratulations you're worth hundreds of millions. If you find yourself thinking that's not enough you're deeply broken and one of the most selfish people in human history, a true 0.01%er.
And again, this is a billion dollar baseline people are talking about. This is the same as people upset about the possibility of inheritance taxes because then they'd only get $10,000,000 tax free. No one is not starting a business because of that, which was your original argument.
Immortality really just means that the odds of you dying by accident becomes 100%.