Even for the ones who didn't do anything illegal, they were certainly "let off the hook" in the sense that the massive bonuses they were paid for economically destructive decisions were never clawed back, and in fact the same fundamental structures of "no skin in the game" and "privatized gains, socialized losses" were preserved and even strengthened in the aftermath of the financial crisis. In the most egregious instance of this, firms which would have been nothing but smoking holes in the ground without public capital injections and backstops were allowed to pay out colossal bonuses to the same people who got them into that mess in the first place.

However, it's also certainly not the case that there were no criminal acts of fraud committed by Wall St execs during the 2000s bubble. Dick Fuld's Repo 105 scam is a great example: https://www.epsilontheory.com/repo-105/