C&P from other site
Because ports have a hard limit to how many containers they can handle a day based on the number of docks and cranes. Port of LA can handle about 25,000 TEU/day. Right now there are 500,000 TEU parked on cargo carriers offshore. By the time they get this 500,000 unloaded there will be another 500,000 sitting there.
This is 100% the result of the lockdowns. Factories went idle, demand slid. Shit got back ordered for up to a year. When the lockdowns were eased, factories started cranking out the backorders and demand for products surged. This caused a huge bubble in international shipments that the ports and air freight carriers just can’t handle. It’s going to take 12-18 months for this bubble to work it’s way through the system.
All of the ports and air freight hubs are handling record volumes of goods, but adding in more capacity can take years.