The question is who such a punishment would have been directed towards. A few decisonmakers make something illegal, and the punishment is given to a hundred thousand employees, not to mention the owners of the cars without emissions cheating (most)?

This is the problem with megacorporations. Punishing them proportionally to the damage they make is unfair, because you are mostly punishing employees and consumers who knew nothing about the wrongdoing. Consequences need to be strong enough to be a deterrent but weak enough to not kill a large employer. That's nearly impossible.

Perhaps the most reasonable thing to do, as has been argued with banks, is to simply not allow megacorps to form, that is, no organization should be to big to fail because we want to allow the bad ones to fail.