Getting a loan against assets is another way of "using" it, so why not make that a taxable event?
Just like now your stock value would not be taxed while it is invested. But now it would be taxed if you use it as collateral for anything. If you don't want to pay capital gains by selling the underlying stock then you can just get a bigger loan and pay the taxes out of that.
There, now you don't have to liquidate but the taxpayers benefit too when the wealth is "used" by the owner.
Just like now your stock value would not be taxed while it is invested. But now it would be taxed if you use it as collateral for anything. If you don't want to pay capital gains by selling the underlying stock then you can just get a bigger loan and pay the taxes out of that.
There, now you don't have to liquidate but the taxpayers benefit too when the wealth is "used" by the owner.