Over the years I've owned (or still own) all of the following; I may have forgotten some as I've bought and sold a lot of basses over the years:
Cortez
Fender
G&L
Music Man (including a 5er)
Rick Turner
Rob Allen
Takamine
Tokai
Univox (I believe ... been awhile, but it was some sort of Beatle bass clone)
What a lot of luthiers have done (Sadowsky, Rob Allen with the Solid 4, Lakland, et al.) is improve on the groundwork Fender laid down. As some have pointed out, a lot of these guys have taken some of the "faults" they may have seen by repairing basses and fixed them in a way to make their own tweaks on the classic format of a P or J.
I still own my Rob Allen basses, so I'm no stranger to a boutique, well crafted bass.
Blame Fender marketing all you want, but like Gibson, even without the marketing, they've been around forever. If they made a crap product, they wouldn't be in business. Plenty of manufacturers have come and gone over the years. It's that simple. Is everything they make uniformly good? Probably not. It's no secret that they had some QC issues at times and didn't have a good reputation for awhile. The recent basses have all been pretty well received. It's rare a company listens and fixes things. Look at the criticism of some amp vendors (not stirring that @!#& pot up, but you know what I mean).
A P or J isn't the be all end all bass for each one of us, but to knock 'em is just plain silly. If you dislike the way a P or J looks or sounds, fine. Boutique basses are not the be all end all, either. Sometimes all you need is meat and potatoes. Most of us who have been around long enough have a few basses in our collection to satisfy different needs for various types of gigs.
I've never had anyone question my choice of equipment for the most part. I had one guy when I was doing the Rush tribute ask why I wasn't using a Jazz (or a Geddy Lee signature). That's about it. I've used my Rob Allen Solid 4 on gigs. No one asked me why I didn't drag out a P bass (which I do own).
I've had odd looks at the Rick Turner Renaissance (gone), Rob Allen Deep 4, and Takamine TB10 (gone), but people got rid of that quickly when they heard 'em.
If anyone asked me to be in a band and stipulated what bass I needed to use, they'd still be looking for a bass player (especially if they want me to play a J - I dislike J basses because I hate how they feel). I use the right tool for the job, period. As a player, that's your job to do what's appropriate. That's the bottom line.
I don't bitch at keyboard players because they may prefer Korg over Roland. I don't bitch at drummers because they use Ludwig over DW. If they sound good, play well, and we're locking in, IT DOESN'T MATTER.
EDIT:
Let's not forget that without a P, J, Gibson, etc., you wouldn't have any of the modern basses which may not even look or sound like a P or J. Someone had to get the ball rolling.
The next time someone asks you why you didn't schlep a 4-banger/5-banger/Fender/MTD/whatever, ask them where their baby grand or Hammond WITH a Leslie (not their $1000 keyboard that emulates everything), DW kit, etc. is since you only play with people that have "real" equipment.
