I'd think that it's just the difference in the markets. Bassists are a LOT more open to new things (witness the huge difference in the number of 'boutique' bass builders vs. the number of boutique guitar builders), and it's not uncommon for some guys to go through a lot of different designer basses. An ALEMBIC guitar is a LOT different than most other guitar choices.
But then on the other hand, there's guys like me for whom there is nowhere else to go: Depite the fact that there's some nice axes out there, I'd buy them while keeping my ALEMBIC. Why? Because not long after I got it, I'd notice the same pickups, hardware, and tone that every other builder uses that are the usual 'off the rack' hardware: The motorcycle equivalent is all these 'custom' builders that get everything out of an S+S Big Book, screw it together, and announce they're in the Custom Motorcycle Business. That's why it's real hard for me to get real excited about the other top basses: They all use EMGs/Barts, ABM/Gotoh bridges, etc., and they all mostly sound alike.
Plus, after the friends I've made at ALEMBIC, aside from the occasional pawnshop find, I wouldn't dream of spending serious money with anybody else. They've almost adopted me and I bought a USED Spoiler that didn't put a dime in their pocket!
So, hell yes I'm instrument loyal, because they're just so customer loyal. Stand behind their work? I've never seen anything like it.
I think we forget just how arrogant ALEMBIC could be IF that was their mindset. There's a lot of high end products in this world where their reps just drip icewater in your face if you're not famous or wealthy (maybe we could hold a contest . . .). Or just for the everyday world: Try calling Fender and tell them you have a problem with a 70s bass, you're the fifth owner, and see how far YOU get!
I know I carry on about this, but I truly feel this way.
J o e y