On top of that it seems to imply that a 20% effective tax rate is outrageous even though that's totally normal for most. Maybe it's not what you're used to as really wealthy person who avoids realized income and has a 0 or 5 or 10 percent effective rate. But it's totally normal for most middle and median income folks who actually pay income taxes.
20% tax on wealth (aka the potentially liquidatable value of an asset) would absolutely destroy anyone using an asset. For a classic example, look at property taxes which are a classic wealth tax. Grandma’s, people on pensions, and even middle class folks who own a home but have relatively low rates of salary increases get destroyed (and have to sell and move out) in places like Texas where property taxes aren’t capped/controlled like California under prop 13 when property prices go up.
Having your house get ‘too expensive to live in’, in fact, is a classic issue with property taxes, and was happening in California - which is exactly why prop 13 happened. And most of those locations the maximum tax is around 1-3%!
‘Wealth’ is not the same as income, because wealth is potential money, if you can sell - and if you sell, you lose access to it.
A 20% wealth tax would mean any asset which doesn’t earning free cash flow returns of at least 20% a year, or which isn’t appreciating at least 20% a year in a risk free way would be impossible to hold for anyone except the most rich people. And even they couldn’t do it for long.
I can’t think of anything which that realistically describes.
A 20% income tax reduces actual cash in hand to 80% of what you’d otherwise have, which isn’t great. But you still get the actual 80% cash in hand right now, and can use it.
You can’t have ‘80% control/ownership for the year’ of a house in a meaningful way, and especially for people actually using/relying on the asset to live, they can’t find 20% (or in most cases even 5%!) of the value in cash for the asset every year. They’d go bankrupt.
It's 20% equivalent income tax rate if you have no conventionally taxable income. Otherwise it's 20% on top of your marginal rate. In his $100 example, you'd pay $1 in wealth tax on the $100 and $1 in tax on the $5 income earned, so your total tax is $2 on $5 of income, an effective tax rate of 40%.
But any real wealth tax is going to have exemptions, only apply to wealth above some threshold, and for the wealthy who structure their finances so as to have little or no taxable income, well they end up paying 20% like all the rest of us do.