California famously insulates people from additional property tax burden on highly-appreciated real estate - and it's clearly still a popular policy among the people benefiting, but it gets a lot less defense from people who don't own those houses than the status quo here gets from people who aren't stock-based-billionaires.

Wealth is closely correlated enough to power that it's worth encouraging people to turn those on-paper gains into liquid forms - even if only to avoid "losing" if the stock then slides back from 100 -> 50. Especially since he can leverage it to spend in other ways!