In all seriousness though looking through guitar mags, especially the American ones, and checking out the ads they seem to fall into two categories: old geezers and metal bands. Perhaps these are the only two groups who get into gear in a big way? I don't really see, "Johnny Burrell plays Brand X pickups" ads appearing soon. I'm generalising grossly here but it looks like indie/rock/etc. bands get the guitar and are done with it whereas metallers seem to be tweakers with their own guitars, pickups, strings and so on. So using the metal or old geezers grouping (I feel a Venn diagram coming on) those would be the two sorts of folks you'd expect to appear in the Pickups forum, and I'd say that was a reasonable approximation of what happens.
Good post! I guess, perhaps, it says something about the types of personalities who are drawn to different musical styles. Generalising grossly (as you said), but many musicians in other genres genuinely seem to regard their instruments as "just tools" and are more interested in what they can get out of them as opposed to what they can
change about them (I do suspect for some, the "just tools" thing is a bit of a pose and secretly they're gear nerds like the rest of us!!).
Personally I used to call myself a metal fan but now (a) metal has evolved into something I no longer recognise and (b) the passage of time has, inevitably, turned me into an old geezer. So, to an extent, I'd be pretty comfortable in one of the overlapping areas of that Venn diagram. Which is probably why I'm still buying guitar mags.
On those "Pickups" threads, I usually recognise the band names but I've only rarely heard any of their music. I guess in another few years it'll be like reading Greek. :|