I agree, it's very much an environmental thing!
If your environment does not help you in learning to play with the setup you have (or change your setup to something they can tech you properly in), then it doesn't matter if you play something too slow, too fast, bouncy, sensitive, dead, or whatever.
...but the advice on forums will generally be to play something slow, no matter what the problem is.
"Help, all my balls fly over the table" -> "Your setup is too fast, get something slower"
"Help, I have no control over my power output" -> "Your setup is too fast, get something slower"
While those might be true sometimes, it's also perfectly possible that someone is trying to compensate for a very slow setup by hitting uncontrollably hard, and doesn't get the proper guidance to improve the effectiveness of their stroke.
On the other hand, you get...
"Help, my attacks are weak" -> "Getting a faster setup is not the answer"
Is that true, though? Not if you simply don't have the environment, resources, feedback required to actually improve your fundamentals. Not if you simply play a VERY slow setup (where you'll benefit a lot from switching to something medium OFF- already). Not if you do well on the direct feedback of a very fussy, fast setup to help you learn proper mechanics.
Not everyone has the same learning methods, again, some do very well on getting literal instructions and copying them, and others need that understanding, that *click*, in order to make things work.
I'm definitely a Clicker. I could have easily drowned in playing my old setup for years without ever understanding how to improve, and quit again.
So I'd say:
"If you have a few years of experience under your belt, but you feel like you're hitting a plateau, do try other setups. You might learn a lot from it. Don't expect them to fix your game, don't expect the gear to be a magical improvement, but feel those differences and nuances and watch how it affects your game. And where it doesn't help."