That’s not what I’m claiming. It’s pretty clear from public records that no one was really paying those rates. The people it may have hypothetically applied to probably didn’t take all of their earnings as taxable income and found ways to avoid paying the top rate. The real rate collected under the 90% regime in the 50s on the top 0.01% of income earners was 55%, not terribly higher than today.

Taxable income is highly elastic as taxes and income increase. See Emmanuel Saez’s paper here [1]. (Conclusion on page 60) it’s a good overview of the inefficiency of high marginal rates.

It’s nice to believe we could just scoop up the wealth of the wealthiest in society and make good use of the money, but it becomes very hard to collect in a hurry in the real world. Most OECD nations with generous social benefits fund them with VAT and taxes on middle income earners. They’ve all abandoned things like wealth taxes and soaring marginal rates for practical reasons.

[1] https://www.nber.org/system/files/working_papers/w15012/w150...