>at one point Taxes in the US were 70-90%.
That figure is highly misleading to cite by itself because the high tax rate also came with a bunch of loopholes and exemptions. That's why despite the drop in the headline rate of 70-90% or whatever, the actual tax take as % of GDP has remained remarkably steady in the past 7 decades.
This chart shows total tax receipts as a percent of GDP, which doesn't seem to address the poster's contention that historically the rich paid a higher share of those receipts through elevated marginal tax rates.