Why should someone else's creative limitations place those same limitations on somebody else's creative use of pedals? Also, I'm sure there are Willie Dixons out there now who play almost only Blues, but I know I don't set genre limitations on myself. I hate listening to 99% of country music, but playing it can be fun to me because it's outside my comfort zone and makes me play differently. Maybe a lot of the bassists you're seeing are Blues or Blues/Rock bassists who similarly play a wide variety of things, but their paid gig (or perhaps just the paid gig you've happened to catch them on) requires little to no pedal use, so they don't bring any, and maybe their other project is psychedelic and they have a huge pedalboard to do ambient soundscapes.
The point isn't what somebody else uses, it's what tools do YOU need to do the job? Or what tools do you want to have at your disposal, whether they're actually engaged throughout the evening or not? At church, I used 0 pedals in over 9 years until a few weeks ago when I started using a reverb pedal. In a classic rock/blues cover band I was in for 4 years, I would rehearse with no pedals, then bring my big board to gigs, and basically use one or two effects in a couple of songs out of about 40 for the night. And my jambands I rarely even practice without the full rig, and use tons of effects throughout the gigs, playing clean on a handful songs. When we played blues in that cover band, I don't think I ever used any effects. One song I used an effect for every time was Bob Seger's Turn the Page, I always used the EHX SuperEgo for a creepy reverb sound. And I used envelope filter when we used to do the Dead's Fire On the Mountain and Help On the Way. Not remembering using them on many others, but I liked having the option.
TLDR: different strokes for different folks.