Taxing the ultra-wealthy is possible, and they still get to be ultra-wealthy afterward. We already do it, the discussion is only “how much?” and what to do with the money. That’s a tractable problem. (Incidentally - the rich have been winning this argument for a long time, as their effective taxes fall and fall and fall.)
On the other hand, proving that a specific piece of income is “economic rent” - I think that’s intractable and only produces loss on both sides. It’s a fight to the death for the accused, a hill they’ll die on. The idea is appealing at a surface level but I can’t see any way forward with it.
Tax people who can afford to be taxed. The alternative is hardly going to work.
