

That’s a non argument. The VAST majority of wealth we are talking about is in equities which absolutely have a clear price. All that other stuff is noise to confuse the point. You really think the wealthy will put all their money in art that has no intrinsic value? And wait a sec, even if they did, what did they just pay for it? That seems like a perfectly valid basis for tax.
None of these values are ever perfect. The point is, we pay a small percentage of our assets every year, but the wealthy have convinced us they couldn’t possibly. Most don’t even “own” anything, it’s all under tax and liability protected companies.
Is this really a cycle? The interesting thing to me is, as others have pointed out, it’s mostly dropped right along with the stock market. Not looking so much like an uncorrelated asset.