Irrespective of what you think of Mötley Crüe and Nikki Sixx (I much prefer the music of Sixx AM whose last CD was excellent)
the man was pivotal for the still most iconic Gibson bass - the TBird - being reintroduced in 1987 and staying in the catalogue that long. It is now 25 years, no other bass model of Gibson comes even close in achieving that time line in uninterrupted sequence. George once observed that and I believe he's right. No Nikki Sixx, no modern TBird. He is to the TBird what Slash is to the Les Paul.
That said, most celebrity bass players are not so terribly helpful in elucidating why they play a particular model. In most cases it is just sticking to what they know and have grown to like. Marcus Miller on a Rickenbacker would still be Marcus Miller, but he shuns the change and the period of getting used to the new instrument. There are relatively few bass players that go through instruments like, say, Joe Perry does at an Aerosmith gig, i.e. twenty songs, twenty different guitars, ten different brands. Hell, I would if there was someone at the side of the stage to hand them to me!!!
Last night at the rehearsal I thoroughly enjoyed switching between an Ibanez ATK, the Roger Waters signature MIM P Bass, the three pup TB prototype and another TB from the early Custom Shop run in 1987 (whose pups are significantly weaker than of any later TB I've played). Findings: The ATK and the Waters' Pee are axes that gnaw their way through everything taking no prisoners to get heard, the TBirds are more musical and sit more in the band sound - audibly, but not clamoring for attention. Did I hear anybody say "a more adult sound"?
Uwe