We don't need to create a property tax for equities to pop the bubble. Old fashion raising rates will do it. Taxing stocks is also problematic. Do you tax at the high water mark, or the average price over the whole year? How does an owner know when to sell? One could easily have an obligation that wiped out a very large part of their portfolio if they sold too late if there was a large draw down. Could a CEO lose shareholder control of the company because of a crash after a Game Stock like spike? i.e. "You had $1B of stock in June so you owe $230M, sorry that the stock in now worth $200M in August. You should have sold."
It's definitely a "please god do something" play, and it would not have the effect anybody wants. I don't think it matters, though, as it's a gambit to provide cover for something else (like raising rates). The Biden administration wants to raise rates but they need cover to do it, because it's gonna fuck up a lot of shit. Volcker's name was mud for what, 20 years? In the meantime, inflation allows them to do a lot of stuff they want - housing reform, wage reform, etc. When the House Democrats wanted a COVID package it was a hurredly-assembled liberal wet dream that the Republicans had to sign because they were over the barrel. They had that shit ready from years and years and years of policy papers and were able to copy-paste together a stone fuckton of socialist largesse. This thing? It's clumsy, it's ugly, it's basebait. I support what they're trying to do but I also agree with your objections. It's a gambit. What will be interesting is what they come up with when this fails as designed.