Mainstream audiences expect Star Trek to be about the Enterprise.
I know that it's long been assumed
this was the case, but I don't really know that it's so. I would submit that the decline of the two series following TNG had more to do with oversaturation than with not having the Enterprise
on the show... as witness that slapping the name Enterprise
(to put it a bit uncharitably) on Star Trek: Enterprise
didn't rescue it from tanking in the mainstream. What seems to me to matter is that the show is fulfilling some kind of real audience demand, not what name is on the ship.
[EDIT: In fact, come to think of it? I think the importance of the name Enterprise
probably applies more
to fans than it does to the mainstream...]