I am a fender lover, I used to have 4 jazz basses and a precision bass at the same time, now tehse days are over but I still have a marcus miller sig , a classic 50 p bass and a jaco sig jazz fretless.
And I know a new fender am standard is in my future.
It's not that they are the ultmiate bass, heck there's no such thing, except if you like a brand and believe that about that brand.
But fender are the first who made electric basses, so they were there before any brand and we all grew up with that sound in our ears, I know for sure that every pro bass player or bass player that are financially ok have tried one.
Their force is that the fender tone can fit any style of music, why? because the invention of electric bass allowed new sounds to happen.
and some music were born with the fender bass,
the british blues boom, soul music, funk, r&b, fusion, hard rock, heavy metal...
so yes they are not the ultimate bass, but they are good in almost every style of music.
But I remember a time, when boutique basses were not that known in the bass community, that when you had a "real fender" (meaning a US fender), that was considered as a high end instrument, and people were like (at least other bassists or guitarists) "oh, you have a fender!!!"
I play high end instrument (fodera) but I can tell that I'll always play a fender also, sometimes when I'm at home, two basses are rotating in my music room, my monarch and my classic 50 pbass.
if I have to audition for a gig, I bring a fender, so no they are not the ultimate basses, but yes they are so great that IMO, if you a pro bass player, you always need at least a pbass or a jazz bass.