The idea of having multiple layers is to make foul play more difficult to cover up; i.e the chances of someone screwing up grows exponentially with every person you add.

That assumes that every person you add has the ability to understand all the details plus is actually willing to do their best to find any remaining issues. Somehow this doesn't match up with my real world experience. It also assumes that convoluted rules will hinder larger companies from exploiting the rules, which is actually the other way around: The larger they are, the better they get at finding loopholes and using them for their own gains. Plus you make it increasingly more difficult to see where your regulatory body has been compromised.

Humans don't work like tech, so adding more and more layers doesn't help really, and I haven't found any organizational form which can inherently prevent humans from being human, it just doesn't exist. For example, all the "paperwork" around safety only works if humans are actually interested in maximizing safety and not just filling out papers.