Yes, but my point is that unless you set out to avoid casting blame, there is a huge incentive to avoid blame by sabotaging the investigation.

But overall the process is tremendously successful at accident reduction, no?

It's not hard for an organization to put a system in place to mitigate any particular individual from making a poor decision. Entering into any decision that is high-stakes inherently justifies the cost of the existence or creation of such a system. For example, RFP processes are often required for any spending over a particular threshold on external vendors. Hiring processes often include input from more than one person.

If the investors didn't do their proper due diligence, then they can take steps to be more responsible in the future. If the founders misled them, then it becomes an economic and political issue of how to address and further prevent such problems.

I disagree. A different approach would be to say "Don't know what happened before, but moving forward Ted is accountable for A, Alice is accountable for B, etc". Knowing what happened before serves zero purpose except to shame. All that effectively matters is what happens from this point forward. You put a process in place this time, to monitor what Ted and Alice are doing. Next time, it's your fault when it breaks, because you were forewarned, and you should have known better. Next time, you know what happened, because you put controls in place.

Or just throw someone under the bus and keep repeating the same mistakes.