It was not meant that the people pay 90%. It was meant that states would pay 90%. A state that collected no tax would pay nothing.
A 90% tax on the wealthy was accepted because the “little guy” thought he was getting some of it. A 90% tax on states would be accepted for the same reason.
If they want a percentage of the deficit, the more they take from the people, the more they get back from the feds. The deficit inflates the currency and states with low taxes see net outflows of wealth to high-tax states in inflation.
There is no such thing as a State that collects no taxes. There never has been one. And there never will be one. The State has the basic services it must provide to its citizenry in order to function as a State. With exclusive access to the tax pasture in its borders it’s going to bring lots more revenue into its coffers - because that’s the nature of government. But as said, State governments are far more sensitive to its voters because it is easier for the voters to quickly effect change at the State level than at the Federal level. (-Way less anonymity of responsibility for taxing & spending at the State level - which is why State income tax is always strikingly lower than Federal income taxes.) But the State will obviously know that it will have to pay some amount of taxes to the Federal Government just like all the other States. So it will adjust its tax policies to this reality.
Now notice how much easier it is for the Fed Gov to tag a 90% tax rate onto wealthy individuals under the current system than it is to tag it onto a State under the proposed 28th. The Fed Gov is not just taxing the rich in that State; it’s taxing the whole damn State. - And because of the equal protection clause it can’t target just one State. Any more than it can target just one rich man under the current system. The Fed Gov has to tax ALL of the States based solely on their accrued revenues.
It should be OBVIOUS how much harder it would be to raise taxes to 90% on States than on to a category of high income individuals. Do you really not see it?