USPS fares better under ePacket packages than the UPU tarifed packages.
3 weeks container shipping on a super container ship vs. even cheapest truck shipping ?
The short-haul truckers at the Port in LA are all independent owner-operators, which sounds like a cool libertarian/capitalist ideal until you figure out that new trucks are super expensive so the operators are almost exclusively buying used trucks, often quite old (and grandfathered into emissions rules). And as we all know from personal experience, there's a lot of soot that comes from a heavy diesel when it accelerates from a dead stop.
And there are no large necks to wring so now you're in the awkward situation of having to go after little guys.
2. container ship is 10g/tonne-km of CO2, ground truck 60g/tonne-km of CO2
3. Shanghai to LA - 10000km, Shanghai to New York - 17000km
So, it is simple math that container delivery from Shanghai plus 100-200km or even more of truck delivery from the port beats any cross-US truck delivery (for the US West it beats even half-cross-US truck delivery). Of course when it comes to the math vs. ideological politics - last season of Veep was brilliant about it :)
Container shipping is ridiculously cheap. See e.g. https://www.joc.com/maritime-news/capacity-cuts-keeping-asia.... Seems around 640 USD from Shanghai to North Europe as per above article/source. This for a 20 foot container. A lot of containers are 40 foot. US has loads of 45 foot containers.
If you'd go very far inland you wouldn't use a truck though; either a barge (inland vessel) or a train.
Presumably they make a profit on the journey to N. Europe, and take a loss on the return.