I think a lot of the Fender appeal comes from the fact they're used by so many of everyone's bass heroes it's inevitable that someone you like uses one. That and the fact they're the most popular basses in the history of the instrument means they will never lose their appeal.
My Jazz is fairly average, sounds like a Jazz but doesn't sound or play a patch on my Warwick, but I wouldn't sell it - I love it's nostalgia and old school tone.