This is true about everything. I know several people who lost big on stocks
Absolutely. That's why I equated this to my friend in a startup who started counting his money before his options vested.
At the end of the day, it's also true of cash and gold and Picaso paintings. They could all have a crisis that destroys value (boy I'm in a pessimistic mood!).
The one difference is that most average people are not buying stocks, gold and art on margin. But the vast majority of those Bay Area householders are heavily margined. So if they need to move during a correction, that's effectively a margin call during a market crash.
If your house is paid off, then it becomes more like a non-margined stock that has lost value. It sucks, but you still exit with cash.
But I have known plenty of people in hot housing markets who have some good equity, but their loan is still so high (i.e. they are so heavily margined), that a good-sized correction puts them underwater. If that happens at the same time as a job loss, they are in trouble. I don't know *any* regular people who buy stocks and commodities (i.e. gold, silver) on 80% or 90% margin.
So yes, it's not inherent in the nature of the asset, but more a cultural problem.