The world is different now than before. Much easier to move and travel, much easier to wire money around the world, the economies of the world are much more interconnected.
However, while on paper the tax rates in the US in the 1950’s were up to 92% for the highest bracket in one year, in reality the actual tax rate paid was much lower.
Here’s an article from Slate which discusses it:
“ Conservatives, however, often try to push back on this version of history, pointing out that those staggeringly high tax rates existed mostly on paper; relatively few Americans actually paid them. Recently, the Tax Foundation’s Scott Greenberg went so far as to argue that “taxes on the rich were not that much higher” in the 1950s than today. Between 1950 and 1959, he notes, the highest earning 1 percent of Americans paid an effective tax rate of 42 percent. By 2014, it was only down to 36.4 percent — a substantial but by no means astronomical decline.
Greenberg is not pulling his numbers out of thin air. Rather, he’s drawing them directly from a recent paper by Thomas Piketty, Emmanuel Saez, and Gabriel Zucman in which the three economists — all well-loved by progressives — estimate the average tax rates Americans at different income levels have actually paid over time. Their historical measure includes federal, state, and local levies — including corporate, property, income, estate, sales, and payroll taxes.”
And here is the original article by the Tax Foundation (which you could say is a bit partisan, but the numbers come from Piketty, who is a French leftist economist):
“ There is a common misconception that high-income Americans are not paying much in taxes compared to what they used to. Proponents of this view often point to the 1950s, when the top federal income tax rate was 91 percent for most of the decade. However, despite these high marginal rates, the top 1 percent of taxpayers in the 1950s only paid about 42 percent of their income in taxes. As a result, the tax burden on high-income households today is only slightly lower than what these households faced in the 1950s.”