There's two elements

1. The legal practice now

Elon is able to avoid taxes since a notable percent of his wealth is in a Roth IRA, which isn't applicable to tax, and then Tesla stocks he has in a Brokerage account he borrows against using Collateralized loans, so legally he's in debt, he doesn't have any income.

He's only hypothetically worth that, not worth that in actual liquid value.

2. The theoritical problems

Let's assume the government decided to increase his tax burden, as we saw with California, he moved from California (A High Tax State) to Texas (A Low Tax State) increasing his taxes would result in a few different things.

1. He has to sell off company assets, like rockets, metal, robotics, etc. which would reduce the productive capacity of his business.

2. He would have to sell off his tesla shares which would devalue his company, and hurt investors eventually leading to less investment.

3. He would have to use the company profits which usually are reinvested into the company as R&D, employees wages, materials, etc. which would prevent the company from growing, and that's assuming the government was nice enough to let him use corporate profits to pay for his personal, and corporate taxes.

4. The Tax Burden would cause him to leave to a lower tax country like Switzerland, Ireland, etc., or to any country that gave him a favorable deal, in exchange for taxes.

Effectively taxes go from value producers to value parasites.

If you want the wealth of the economy to grow then reduction of taxes generally helps overall, as it allows individuals to do what they want with their own money.