High marginal tax rates (the worst of which affected few, btw) did not hinder the development and advancement of the middle class in the postwar era. That era was marked by extraordinary American industrial dominance and prosperity, an era which has ended. The high taxes were made possible by such growth and not the cause of it. We are now in a secular period of anemic growth. Taxation as a means of redistribution will not produce the changes needed to propel the middle class forward in a manner it did in from 1946-1980. Only a paradigmatic cultural shift will achieve this, and such a change is nowhere in the offing.
The redistributionists can't face that they and their charges have grown fat, sloppy, and lazy, and have become accustomed to ongoing plenty and have become filled a sense entitlement. We are not in a post scarcity world.
Lastly, smarter men than I did not believe differently decades ago as smarter than I was and is rarer than the unfortunate heir paying full estate taxes.