The cost of living within commuting distance of a Ferry Terminal is absolutely insane. The salary WSDOT pays ferry crews is abysmal. The crews also are required to have TWIC cards and a shitload of other training and certification which pretty much makes them eligible for maritime jobs paying 10x what WSDOT can pay.
The end result is that the ferry system isn’t sufficiently staffed. Also, would you like to stand in the freezing cold, pissing rain at 3am?