Have you ever had one of your basses go flat mid song? I have, fortunately when practising, my mid 80s five-string active bass goes flat over a less than 30 seconds, when it goes. It's quite extraordinarily dramatic and not what I would expect, but it does happen.
Having a switch over (which is not difficult for anyone with the ability to design a decent preamp) is an insurance policy, not a lifestyle choice.
MInd you, I have never really understood what advantage having a pre-amp in the bass has over having one in a pedal (or even a decent one in your amp). Sonically the only possible different so a slightly greater signal-to-noise ratio that can just as easily be achieved with a decent cable...