Right. My point was in response to excuses being made elsewhere that the nature of large companies mean these executives cannot be personally liable. So if we accept that the nature of huge companies is no one can be liable (I'm not convinced yet) then it would be time for capping sizes or outlawing structures.

Keep in mind the US already has laws around corporate structures and conflicts of interest. (Even if they're selectively applied.)

The nature of any size corporation is to have one person in charge. In terms of assigning responsibility I'd think that works better than the alternative you'd get by breaking it up. Namely a bunch of cooperating smaller firms only doing part of the job each, and able to point the blame at each other.

We heard the "too complex to understand" excuse a lot regarding the pricing of subprime debt. Except a lot of people did understand it was a problem. It's basically the "I'm too stupid to know what I was doing" defense. If we accept that defense and try to make regulation to protect them from failing (as was done in finance back then), we basically allow stupid people to continue to be in charge rather than being replaced as they need to.