Sure but if you bought a broad index you were fine

Again, that depends on how long you hold and when you cash out. Most people don't get rich: https://archive.nytimes.com/screenshots/www.nytimes.com/inte...

I'm sure there are studies out there on the ratio of upper-middle-to-upper class households vs not, adjusted for inflation, with surveys on how they invest (if they do at all) with other factors accounted for. I know for sure that the total number of households who hold index funds (50+%) [0] far exceeds households that have a million+ in assets (10+%) [1]. If index funds were some magic bullet investment vehicle for multiplying your money, we'd see better ratios than 1:5 with only the top 20% becoming wealthy-adjacent (and that's provided that 100% of the millionaire class got rich via index funds and not other means like real estate).

[0] https://www.ici.org/news-release/ici-report-shows-mutual-fun...

[1] https://finance.yahoo.com/news/guess-percent-people-1-millio...

edit: as a corollary, I was just talking about this with someone who works in finance and the sentiment amongst ICs like them, they say, is that this is definitely a bubble that will pop at some point. The only contention is how devastating the effects will be, if it'll be a slump, a recession, or a depression.