My former neighbor from LA (who was a longshoreman - he just passed) as telling me last month that there is an acute shortage of people willing to work on the docks. They make bank (like 120k annually working on the docs).
He was telling me last month that the owners of the docks were offering cash incentives to work triple shifts just to clear out the back log of ships, sitting offshore of Long Beach, CA.
Doug is spot on with the inability to move the containers off the ships and onto either rail or truck.
Oh that's another story. The trucking industry is also struggling to find drivers. Many of the young people who are thinking of going into the business see automation replacing drivers in the future, and don't want to get into an industry where automation will replace them in the future.