As an unrepentant gear-head and tone-quester, I absolutely LOVE the idea of bringing several basses for fretted/fretless options, tonal variety etc., and really tried to make it work in practice. I would devote precious space on my board to various EQ/boost options that would facilitate easier switching, plan set lists ahead of time so I could be deliberate about when instrument changes would take place, choose gear carefully, practice switching instruments, and rehearse as if it were a gig.
In reality, however, the extra setup, stands, logistics, time, reduced flexibility (BL makes a last-minute change, calls a different tune, etc.) and sound challenges turned it into something WAY more difficult to pull off well, with a lot of effort and not much to show for it.
I would TOTALLY be into swapping out instruments (every song!) if I had a crew, and I would completely geek out about the technical production aspects of how to make the changes work well. However, I'm just a day-job Joe who tries hard to bring A-game value and musicality to every project, and trying to do instrument changes works against all of that.
Gotta say, though, that I still love seeing folks that put in the effort to do it and make it work well, so thanks to everyone who carries the torch.