Couple oversimplifications there. "Roaring Twenties" were fed by the nascent Federal Reserve ballooning the economy through the 20s and an inevitable contraction occurring at the end with a huge regulatory clampdown, expansion of the state and prolonged low interest rates/inflation into the 40s. The "top marginal tax rates" were essentially base rates and the effective rates paid were close to half that. A more meaningful metric is federal spending as % of GDP by year:

which, taking into consideration that the economy has been growing in the last 80 years, indicates that federal spending has been gradually increasing ever since. The spike in the 40s is of course the enormous WWII spending. It's also critical to take into advantage that the general state of technology/industrial infrastructure is light years ahead now than where it was at the beginning of the 20th century.

It's pretty universally known that the entire working class has basically been left behind by economic growth since the 60s/70s, while government spending has continually increased since then, and simultaneously, corporate profits have also kept pace with economic growth. Which really begs the more important question, what specific mechanisms in our economy are actually producing these outcomes. I feel like people spend a ton of time arguing about things they think will curb the effect instead of asking why it's happening in the first place.

Or in plain English: the system isn't producing equality of ownership, or equality of proceeds from production/labor - why not? How can we fix that without just piping half the economy through the government? That's the real question.