We already do have such a tax: inflation. The fed increases the monetary supply and uses it to buy treasuries which help fund the government. The problem is t

We already do have such a tax: inflation. The fed increases the monetary supply and uses it to buy treasuries which help fund the government. The problem is the rich have lots of options so you need to consider second order effects. If you print lots of money (as we are now), people and especially the rich tend to exchange their dollars for assets, such as stocks, art, etc. If you attempt to tax those assets as well, people will purchase other untaxed assets. I'm also not sure it actually matters as much as people think. It's not like Gates, Bezos, Zuckerberg, or Musk are using their funds to compete with the average person, IE buy up all the beef. Them having less really won't make us more efficient at producing food or increase the amount of housing available in cities.