The bond holders and shareholders didn't have insurance nor did the counter parties (mostly other banks)[0] but didn't effectively assess the risks despite thousands of analysts between them. How could/should a retail investor with a few hundred or thousand dollars assessed the bank's creditworthiness? A few analysts, economists and traders saw it coming but most did not.

[0] I know they were largely bailed out but there was no promise in advance (and we probably agree that they shouldn't have been bailed out to the extent that they were.