The same podcast included a story about an entrepeneur _trying_ to ship empty containers but none of the shipping lines would eliminate the part of the lading contract that says they own the containers when you're done with it.

Anyways, right now the bottleneck isn't shipping containers in China, that was an early pandemic logistics story.

It is worth it in the grand scheme of things but there appears to be no mechanism to charge all the benefitting parties. There is cost shifting going on that’s creating bottlenecks