It's an extremely competitive industry that has seen government funding as part of the industrial policy of several east Asian countries. Right now even Korea, one of the largest shipbuilding countries, is having trouble competing with the Chinese shipbuilding industry:
>However, despite these significant contracts [above], the Korean shipbuilding industry is facing a growing sense of crisis. According to industry sources on Oct. 3, out of the 191 container ships of 7000TEU (1TEU = one 20-foot container) or more ordered this year, China took 177, accounting for 92.7%. This shift has been particularly evident in recent large-scale container ship orders by global shipping companies, which have increasingly favored Chinese shipyards over Korean ones.
>The industry assesses that China is gaining the trust of global shipowners by successfully carrying out projects with low prices and quick delivery times. In fact, it is reported that there is no longer a significant difference in delivery schedules between Korea and China.[0]
To be clear, Korea is still a major player in shipbuilding (basically tied with China) and based on an article from last year[1] it seems that they focus more on other ships besides 7000TEU. It is probably impossible for the US to enter this market in any reasonable time frame and it would need government support like in Korea China and Japan. Even Japan, which was the largest player in the shipbuilding industry for decades has lost its marketshare to Korea and China. The costs saved by not being subject to the Jones Act probably don't make up for the cost of those ships. In 2013, US container ships costed 5 times as much as foreign ones, and it's probably more than that now.[2] Maintenance is another factor.
[0] https://www.businesskorea.co.kr/news/articleView.html?idxno=...
[1] https://www.kedglobal.com/shipping-shipbuilding/newsView/ked...
[2] https://sgp.fas.org/crs/misc/R45725.pdf