That is the kernel. Free trade will force inefficient national industries to compete in an international market rather than relying on domestic markets. In the UK in the 70’s and 80’s the car industry was on it’s knees with dated products, poor quality, poor management and confrontational as opposed to co-operative unions. Over the past 20+ years this has turned around with Jaguar Landrover, Toyota, Honda, Nissan, Bentley, Rolls etc all making cars both for domestic and export markets. All due to free trade.
In the 1930’s having protectionist policies (including the Jones Act) could be justified, but look at the economic background.
International trade volumes were miniscule compared to today.
Consumer goods were almost non-existent - valve radios, domestic furniture and early automobiles, bicycles etc, so to trade these internationally was slow and pro rata very expensive.
In a day of car carriers and box boats, and with globalization free trade is essential. No country can be an island, even our friend Kim has come in from the cold so perhaps Trump’s stance is a negotiation ploy.
The US ( & Canadian) coastal industry is a geographically isolated maritime system. It can and should thrive with modern, fast cargo efficient vessels. Manning by so called 3rd world villagers will be unlikely - flight costs, visas, work permits, insurance etc will reduce the economic advantage.
Such systems happily exist with free trade - Russia - Volga Don max vessels (Russia, Ukraine, Iran etc)
North Europe Short sea with vessels to fit the various waterways - Kiel canal etc. Both systems overlap in the Baltic and Med, but both are systems that have evolved through free trade.
Just mu 2c from across the pond.
https://www.wilsonship.no/en/fleet