Even when the stock market crashes the rich don't get poor. They can seemingly lose ungodly amounts of money exceptionally quickly but even after all that they'll still be rich because being rich is a comparison: If everyone on a mountain falls down the ones at the top will still be there.
I think I crack the top 10 percent income earner I agree (not sure where I am in the USA net worth wise). I don't consider myself rich, but that is very much in part because I live in NYC, but if I didn't live there I probably wouldn't be 10% earner. A big market change could have very significant impacts on my life, housing, etc. Fuck the 1% percent though.
One thing I have noticed about folks that talk about income and wealth in my bracket is that they talk about Stock benefits like options, RSU's, and ESPP as income. When I was making salary and around folks under 75k no one really talked about those types of benefits as income meaningfully (partially because they didn't get it or didn't get a significant amount of it). But for those high income earners in the top 10% that factor their stock as part of their income lifestyle, that puts them more at risk for greater income swings in the event of market crashes to a certain degree (assuming job loss doesn't occur).
Click on the link. Literally the first thing in the article is a graph over time.
tl;dr it was about 80% in 1990, and is now 92.5%. Or alternately, the bottom 90% of the population owned 20% of stock market wealth in 1990, and now they own 7.5%, so around one third as much as a generation ago.