I don’t think that’s accurate. It may be de facto accurate in the sense that most people don’t have much in assets to take if there is a default, but I think a well-off person who doesn’t have all of his net worth invested in a house can’t simply walk away from a bad outcome and be free of it. He’ll be sued and wind up with his other assets exposed.
Some of the federal law changes under the Obama administration, I believe, did retroactively relieve borrowers of their obligations, but the original contracts were mostly full recourse.
Actually, here’s an article that gets into this issue. It looks like in some states it is non-recourse.
Edit: as the to original question, I think some areas of the country still have downward pressure on prices. If you put your life savings up as the 20 % equity, you may well find it cut in half in a rather short period of time. At some point that pressure will reverse and head the other way, but its not showing signs of it outside of some regionally hot markets.