There may be unintended consequences in forcing successful founders to over time sell down a controlling stake in their company.
A lot of companies operate close to break-even or even at a loss. What happens with the owner of a $2m / year company must come up with a 10% wealth tax amounting to $200k, but the company is operating at break-even? Expenses must be cut to pay the tax. Ultimately hurts the lower and middle class the most.