No. It decreased massively and then went up again so now we're back at where it was back in 1900. This significantly challenges the "if America’s rich families

No. It decreased massively and then went up again so now we're back at where it was back in 1900. This significantly challenges the "if America’s rich families in 1900 had invested passively in the stockmarket" e.g. the equivalent of S&P 500 if adjusted by inflation was in 1982 was well below it's 1929 peak. Almost all growth happened after that.