Making a good progressive tax scale is a task which a freshmen can do in a hour. The problem is not a better tax scale, the problem is how to find actual shit to tax. Doing nothing, we have the modern state of economy, when there are poor people having small to no tax basis, then "middle(lol)" class exposing all their assets and funds fully to the tax office and paying maximum taxes on this planet among everyone because of that, and then passing middle class we have people becoming richer and richer but "somehow" paying fewer and fewer taxes, culminating in billionaires who legally have zero assets, zero saving and zero income. You tax tax such a person 5%, or 50% or over 9000%, the end math will always be zero. Good luck funding UBI from taxing billionaires :) . And salaried people actually paying max bracket taxes already can't fund the whole planet by themselves, math is not mathing here.