Found an excellent substack piece on why the United States continues to fail at shipbuilding (and has actually never been good at shipbuilding).
Some choice quotes
I hate over quoting an article, but there are just so many good peices of information contained in this peice. I highly recommend you check it out as the author clearly put a lot of work into documenting the trials and tribulations of the US shipbuilding industry.
I think it makes a strong case that the US should be looking to its foreign allies to help with surface warfare\supply ship shipbuilding. The current US naval industry can be turned towards submarine and aircraft carrier production which I think is more specialized and likely doesn't have much overlap with surface construction.
I saw from some other poster that American workers were magically 4 times more productive than any other workers in the world including China. I think the solution is just hiring 1000 more people and like you can get all those Constellation FFGs rolling off the line in no time.
Jokes aside, tl:dr version: Politics.
Do you think you can be the President that can convince the people that USN ships should be built in Japan, Korea, or Italy? It's as simple as that.