Also, the US commercial shipbuilding industry has always been small. WW2 was the exception where built lots of ships mostly in temporary yards. Since WW2, it has struggled. Naval shipbuilding has been the big part.

It is a lot of pain for reset of economy for protecting a small industry. If US wants more naval shipyards, then should incentivize building them. I get the impression that there has been much reason for yards to improve protected from competition.