That way lies the fateful curse suffered by millions of messageboards littered across the web - dozens of empty forums with two threads in each. They all used that utterly untrue pseudo-philosophical movie quote: "if you build it they will come". The truth is, if you build it, it will sit there empty.
If it's a lot of work to make that kind of thing happen, I would certainly understand. Or even a bit of work, I guess - after all, you don't seem convinced it's worthwhile, so. . .
Would a poll in the general forum help to persuade you (assuming results were, y'know, supportive of such a move) ? Perhaps a closed (to non-logged-in users) poll? Or one that records usernames, at the very least.
Sound reasonable?
Start talking about it and make it needed.
I did try that once or twice*, when I came across a thread or two, after
the 3e fora were altered, to "include" every other "legacy" D&D system as well. Now, I
know there are quite a few gamers who are members here, who are also into OD&D (or the like), and who love to talk about it. But in
at least one of those threads, I was - AFAIR - the *only* person responding; the only reason *I* was there in the first place was because I was heavily into 3e/2d0 at the time.

Because, yeah, those fora are still (even now!) very much 3e-oriented. That's their history, their "placement" if you will, and it just seems everyone (OK,
nearly everyone, and the couple of exceptions have apparently given up anyhow) views them as 3e-centric, and therefore uses them as such, or ignores them altogether, accordingly. When I tried to contribute to said thread(s), the whole thing felt very awkward, as though older D&D had been sort of jammed in, amid a - at best - totally indifferent crowd of regular users.
* And yeah, I *have* discussed some OD&D/BD&D/1e/2e stuff in, f'rex, the general forum. . . but there are limits as to what should be included
there, of course. Or so it "feels", so to speak. Specific 4e stuff goes in a 4e forum, specific 3e stuff in a 3e (++!

) forum, but. . . other D&D stuff? Well.