I think the port thing is destined to wind down. Mostly this is a temporary fluke - unless climate change or other factors diminish what ports can do.
Past that, would the potential volume carried by rail compete with megaships+air? I don't know the numbers but am doubtful.
My understanding is that California has passed laws that have highly discouraged in-state trucking investment, as many older vehicles became unable to be driven in 2020, and entire classes of engines being banned by 2035.
Ports in other states will have to take up the slack.
The ports of LA and Long Beach also have entrenched labor issues that make modernizing virtually impossible.
http://en.wikipedia.org/wiki/Alaska-Alberta_Railway_Developm...
See also:
http://en.wikipedia.org/wiki/Prince_Rupert#Seaport
>A belief at the beginning of the 1900s that trade expansion was shifting from Atlantic to Pacific destinations, and the benefit of being closer to Asia than existing west coast ports, proved wishful. Reduced transit times to eastern North America and Europe did not outweigh the fact that rail transport has always been far more expensive than by sea. The opening of the Panama Canal in 1914 exacerbated the problem.
It's hard to beat boats!