When did they change to a plastic bearing? A dealer should know that this should be checked whenever the boat is in for service and it's on the trailer.
Also, there is usually an upper bearing and a lower. The worn one was left in far too long and while I don't want to point fingers, this is one reason boat owners should take their boat in, occasionally. Many boat owners want to do their own service, for a variety of reasons but they don't have access to the same amount of information as a dealer's service department/tech. For this reason, some service steps are not addressed and can lead to failures of the boat's components and systems.
That shaft will be replaced, right?