Youre right about income tax and to some degree income tax does primarily effect the wealthy except the brackets haven’t been updated to reflect inflation and the new ultra wealthy class appropriately. The other thing is, many of the wealthy don’t have incomes in the traditional sense, and it makes no sense to differentiate capital gains from regular income. The argument that you don’t want retirement investment income taxed as regular income tax is a little moot since that’s why we have tax advantaged retirement accounts. If those accounts aren’t enough for all retirement investments, maybe those limits need to be increased or the way the tax advantage works for them needs to be changed.

Past failed attempts are also a good point, but to me they sound more like administrative failures rather than a failure of that type of policy. In the US we already have some wealth taxes on the value of homes and cars. Some of these failed European policies seemed to define wealth poorly and as a result either weren’t fully taxing wealth or spending more resources on administration than collections. But banks already do a great job of assessing an individual’s wealth. This is how the ultra rich are able to get huge lines of credit to play with rather than having to use their own capital directly. I don’t see how the government can’t use similar systems to calculate an individual’s total wealth. And the argument about the wealthy fleaing the country are also a little moot in the US. The wealthy in the US make money off of American tax dollars. Amazon/Bezos is rich because the US government started using AWS. Tesla is successful because the US uses their influence in South America to cost effectively obtain raw materials for batteries (not to mention those tax credits on EVs). There are all the military industrial companies, and the insurance companies. If the government had the backbone to say Americans who got wealthy using the American market have to pay taxes in America or they lose their right to sell to the American market (government or to the public), no one is going anywhere.