The article I linked does a fairly good job explaining it. Basically if you are a container owner, you can charge 10x the price for containers from Shanghai to Long Island, while the other way it’s almost a loss since it’s returning empty.
The decline in ships waiting just offshore of Los Angeles/Long Beach continues to be touted as a sign that port congestion is easing — despite the fact that the true number of waiting ships has not actually declined.
Not true in general. The port of Long Beach is down 5% year-on-year (the third month in a row that is down compared with 2020) [0].
[0] https://gcaptain.com/amid-record-breaking-year-port-of-long-...
"Through November, the Port of Long Beach has processed more than 8.6 million TEU, up over 18% from last year and already surpassing the annual record of 8.1 million TEUs set in 2020."