What you say makes sense if the wealth tax is applied on ETF/index fund holdings, but for most founders, the wealth is concentrated in holdings in their own company. On average, across all founders, the asset growth might be 5%, but for each individual there is significant variance. For nearly half of founders, wealth tax would take 1% on either a flat or a depreciating asset..
Keep in mind that "flat or depreciating" companies are way more common than you think. Not every company enjoys the annualized returns of the S&P500. Almost any non-tech or non-tech-adjacent company has remained either flat or depreciated, in the last 10 years.
That's the entire reason why lay people invest in the index, because it's relatively safe from depreciation. Most of the super-wealthy don't achieve that wealth on the back of the S&P500, they achieve that on the back of owning a single zero-to-one stock. It's one thing for the company to grow from 0 to {insert equilibrium valuation}, and another thing entirely for the company to continue to grow at a rate that outpaces inflation.
A 0.5% wealth tax is not going to make you poor. It could, _at absolute worst_, make you worth "only $50M". If you still manage to go from $50M -> $20M, a wealth tax had absolutely nothing to do with that.
As well, although it's not explicitly mentioned, I would expect any floor-value (such as $50M) to be set to keep pace with inflation.
Your argument doesn't refute my central argument, it refutes an unimportant implementation detail.
Are you saying that most of the super-wealthy do not (at least to a certain point) diversify their investements? Or is your point that most super-wealthy individuals acquired their wealth themselves by investing (or founding) a single corporation themselves?
The article does not model asset growth in any way, and if you do model asset growth you would get significantly different numbers.
The only reason we are even talking about wealth tax is because of the crazy unable to be funded programs some people are proposing. These programs sound nice on paper until you do the math on them. Then they realize they can not pay for it at all.
Remember wealth != cash value.
Wealth is not the same as cash value. It is easy to miss the distinction. We may be agreeing? We also already have a 'wealth tax' on many items already. We call it property tax.
"Being concerned with inequality" doesn't give people the right to go and arbitrarily expropriate other people's assets.
We absolutely do have that right in the US.
State governments may or may not have that power, according to their own Constitutions (most, I would imagine, do.)
Take a building, any building. Sit on the building for 50 years. How much is building worth? Probably way more.