We're out there, OP. I'm 22, but now that I've been involved for four years (starting as a bottom but now as a Master with a slave of my own), I've got enough experience to stand on my own two feet and know what's what and how its done. I've never actually come across the term nextgen, but it feels appropriate enough to me. Certainly the flavour of BDSM I practice has drifted from the strict praxis of the Old Guard, though I've enough knowledge of that way to have a profound respect for it.

But, tangents aside, I know what you mean, a lot of relationships in our community do seem to come with a large age differential. I think most of the responses have hit the nail on the head, but one idea has been missed- a lot of new, young subbies are just that: completely new to this world and looking for someone with experience and maturity to guide them, and whilst experience and maturity don't necessarily correlate with age (there are a whole lot of older doms who I've seen at work who don't seem to have a clue what they're really doing) it's a cue that a lot of people take. Another good reason is that a lot of the more prominant and visible people in the kink community are in their 40's or higher, and they use that position to go after younger subs, either to protect them or simply because they enjoy younger partners.

But there are skillful, worthy younger doms out there too, so don't be discouraged.