I know you are right, but I know of too many people, myself included, who bonded with basses, let them go, only find that nothing can really replace what they had.
For what it is worth, Bobby Watson created his iconic work with his P-bass,
that is the sound of his that is history. Playing a Fodera now does not change Rags to Rufus or Off the Wall.
It does fly in the face of him using only one bass though, right? That's why I mentioned it. And even guys who use multiple basses afterwards don't affect their previous recordings so that's an interesting point you're making.
There are also plenty of folks who never really figure out what one bass is capable of.
I know what you mean but I've seen just as many if not more play different basses and get the results "they" want. It's more of a romantic notion of the "one man, one bass" thing than actual reality IMO. Worse, I've seen even more buy bass after bass trying to address an issue that really doesn't fall on the bass at hand.
I personally love playing basses that are fun to play and since it's not cheating, I don't see a good reason not to play more than one. I know what all of my basses do in my hands. And I've hung onto the ones I've really loved so I can still grab them whenever I want. Best of both worlds I guess.