[WJW]

Sure, but crashes don't make up even 10% of the total amount of time. If you needed liquidity at any other time, having been invested would have been the right thing to do. In addition, there are many options available to make more liquidity available at all times, from literal (put) options to just simple diversification and holding a part of your wealth in cash as an emergency fund.

It's good to focus on the bad outcomes as well as the good outcomes, and most people do indeed make the mistake of only considering the good outcomes. But looking at only the comparatively rare bad outcomes and then concluding that investing in the stock market is a bad idea is just availability bias.