No one could be held responsible for the people affected by either of those accidents. Metropolitan Edison was only responsible to the regulatory agencies and their shareholders. Russia was a dictatorship.

The problem with regulatory agencies in the US are, they're not directly voted in by the public and they can be corrupted by bribery or regulatory capture.

Further violating regulations results in monetary fines or maybe getting their license revoked, but not jail time for the bad actors.

Note that voters mostly cannot be bothered to learn about such boards when they can elect them. There are alwaysa number on my ballot where I find out from seeing my sample ballot and I have no clue how to find out how I should vote after trying to look.