I would like to see maritime law changed to make the insurers liable for these costs, though. It's not okay that the federal government has to pick up the tab for incompetent maintenance, or contaminated fuel.
Where do you get the idea that the insurers are not liable?
The post above by @floobydust suggests they might be on the hook for a maximum of the ship's value + cost of cargo transport. So probably north of $100mn, but well short of the cost of one replacement bridge.
Regardless of the liability, I would advise not legislating in the heat of the moment and pondering things very carefully. Legislating too quick makes for bad laws.
All countries, including the USA, have many ways of limiting liability because it is considered to result in a benefit to society in the big picture. Limited liability corporations, bankruptcy laws, etc. might seem unjust in specific cases but they benefit society as a whole.
Governments already pay for infrastructure out of taxes because it results in economic activity and development and well being.
If the government required every business to have unlimited insurance coverage then many businesses would have to shut down because it would not be affordable.
I do not know but maybe if the USA required too much insurance or other requirements for ships and other forms of freight then that would result in much higher shipping costs or even in some ships or companies just refusing to go there.
It may well be that the USA considers the cost of rebuilding a bridge every few years more affordable than putting very onerous requirements on ships.
Legislating in the heat of the aftermath often makes bad law and has unwanted consequences.
Laws have to be considered and crafted very carefully and even then they often backfire.
The Jones Act requires vessels transporting freight within American ports to be American built and crewed. The ostensible purpose was to protect the American shipbuilding industry. In fact it totally backfired.
https://www.cato.org/publications/policy-analysis/jones-act-burden-america-can-no-longer-bearI would advise to tread slowly and carefully and consider changes with great care.