There is a bit more to the story than a 1% wealth being "equivalent" to a 20% income tax. The primary difference is that unrealized gains are taxed by a wealth tax. We need a mechanism for assets to be sold by the richest in society. If those with assets keep accruing more assets the median person will suffer. When we're talking about real assets (housing, retail shops, warehouses, land) we don't need to be concerned about capital flight. The assets are still there on the ground. Reducing the cost of those assets is exactly what we need to help a local economy.

That being said, the richest are effectively _not_ paying the highest marginal tax rate considering all the tax structuring they do. Claiming that they would be paying the highest income tax in the world is misleading, for one. Secondly, the richest in the world _should be_ paying the highest income tax.

If those with assets keep accruing more assets the median person will suffer.

How will they suffer? The people with assets, to realize a benefit from them, have to spend money. If they don't spend the money, then what's the problem?

When more assets are sold than are bought, that leads to the destruction of assets on a broad scale. It's the economic equivalent of eating one's seed corn. This would not be good for the median person. You can and should tax land (meaning the land value component of real estate in general) and natural resources more generally, but that's an entirely different game: it has next to nothing to do with wealth taxes as generally understood.