I think it would be more realistic to heavily tax inheritance and re-evaluate trust based loopholes.
I mean, you’re clearly moving the goalposts here. We’re talking about tax on unrealized gains for the wealthy, not sales tax, property tax, or taxes on the bank.
If you’re able to keep taking out new loans to pay off the old loans until you die, with an appreciating “unrealized” asset as collateral, then yes all that money is effectively tax free if we’re talking about income tax and capital gains.
There is no such federal tax in the USA.
And it is just ludicrous to suggest that stock holdings cannot be subject to a wealth tax. The value of stock holdings are established all the time when the wealthy provide their net worth for their business dealings.
The IRS requires me to submit the value of my IRA holdings as of the end of the year to determine how much will be taxed the next year (by forcing me to withdraw a dollar amount - determined by the asset value of my holdings - which vary minute by minute when the markets are open). So, I guess it's ok for the IRS to measure my wealth each year to enable the IRS to collect a tax on that wealth - but some how you say that's impossible to do for billionaires?