That someone failed to make money on the market doesn't necessarily mean they were wrong, it may just mean nobody gave them a pile of money they could afford to risk.
Now we have a bunch of presidential candidates that tell me they are going to print money all day long and a bunch of people who "know better" telling me that won't cause inflation to spike. ¯\_(ツ)_/¯
It was much more difficult for housing. The Big Short tells a story about how even if you knew housing was over valued it was very difficult to short, and the ones who did almost lost everything.