I don't know anything about industrial and PE "scenes." I've never attended any gathering or event that would attract something remotely close to an industrial or PE crowd musicwise. Noise, sure, but industrial and PE? That's more than a niche thing as far as I'm concerned, and I'm not sure I'd be into attending such events to be honest. I have no idea how widespread the use of modular synths is within the industrial and PE scenes but I assume it came with the recent boom of eurorack a few years ago, although I'd make a difference between proper industrial music and PE. Anyway, again, read any conversation about people wanting to make industrial or noise music with modular synths online and you'll see the names that come up the most.
PE and industrial music are indeed, "special interests", but modular synth is an entirely different world, and a much more geekier one at that. The names I mentioned (and that you know) offer kind of "full package" modules that are convenient for the people into such kind of sounds, and I think that's why they're brands everyone into this kind of sounds and who wants to get into eurorack will look up or search to buy modules from. They'll do it for the same reason they bought an MS20 that they'll probably use to 8% of its capabilities. I don't mean that in a bad way, more than modular synth is a hobby whose learning curve is pretty steep and not many people want to spend the time getting into (because they don't care about what an envelope follower, or a sequential switch, or an analog shift register is, and that's OK too, although limiting if you want to learn how to use your instrument better), and it's much easier to buy a module that'll give you an immediate result rather than 3 bland utility modules that'll give the same result soundwise or something close enough when patched together, yet less recognizable.