One of those variables is likely tax rates. Back then, federal income tax was way way lower than what it is today. At some point the highest income tax bracket

One of those variables is likely tax rates. Back then, federal income tax was way way lower than what it is today. At some point the highest income tax bracket was 7% but today it's 37%. I'm not a history buff but Google says social security taxes first started in 1937. That could be potentially another 13% less taxes paid back then. Also Google says corporate tax was hovering around 12% during the 1920s but it's upper 30%s now. Imagine how fast you could gain wealth if the govt. only took 20% of your income instead of 50%.