Eureka will never be a cruise ship destination. In the mid 90's I worked at the Eureka Inn and occasionally drove their trolley giving tours of the downtown area to the passengers of the few cruise ships that came in. Most passengers complained about the stop and very few were impressed with Eureka. Who wants to freeze in the fog while seeing empty buildings and homeless people.
There is no economic reason for Eureka to exist. It was built on fishing and logging, neither of which exist as an economic base anymore.