Saying "nearly everyone" was wrong and blindsided by it is a bit of a stretch. Not everyone that saw it coming profited from it big like the now fabled protagonists in The Big Short. But to people who chose to pay attention to it, the issue was known and well publicized ahead of time:
The key to 'seeing it coming' of course, is to first willingly accept the possibility that something might happen, and then actually look into it. The issue was that many people were just not entertaining the possibility at all, and therefore not bothering to look into it. The information was all there for anybody to see, but this was a case of people missing the gorilla in the room because they were too busy paying attention to the game[0].
https://youtu.be/tZaHNeNgrcI
https://youtu.be/kFd8YluIVG4
The key to 'seeing it coming' of course, is to first willingly accept the possibility that something might happen, and then actually look into it. The issue was that many people were just not entertaining the possibility at all, and therefore not bothering to look into it. The information was all there for anybody to see, but this was a case of people missing the gorilla in the room because they were too busy paying attention to the game[0].
[0] http://www.livescience.com/6727-invisible-gorilla-test-shows...