>It's not, and I don't think anyone said it was.

Yeah you did. You wrote "he couldnt turn it [his illiquid assets] into cash even if he wanted to".

>The problem is in the calculation of "net worth".

That is not a problem.

Let them value their own assets. If they value their ming vase at $10k then the government reserves the right to buy it for...$10k. They might get away with avoiding paying taxes. Or the government might get a bargain. The incentive, though, is to be scrupulously honest and accurate.

Some people obviously wouldn't like being put in such a position.

> And, more importantly, the difference is that people choosing to put their money into something is not the same as enabling it to be taken by force.

Im not 100% sure but I think this falls under the category of just saying "wealth taxes not fair!"