Hm. Let me throw out several points in random order:
-- I don’t think LW is a “general-interest” forum. Not even “relatively”. However that’s fine—there are really no such things as general-interest forums because their lack of focus kills them. What you have, actually, is online communities some of which spend their time chatting about whatever in the general section of their forums. But that general section is just for overflow, the community itself is formed and kept together by something that binds much tighter than general interest.
-- If I rephrase your post along the lines of “LW is a web-based club for smart people. How do we get more smart people to join our club?”—would you object?
-- Size matters. In particular, online communities have certain optimal size for cohesiveness—be too small and it’s just a few old-timers making inside jokes; grow too big and you drown in a cacophony of noise. I’ve seen online communities mutate into something quite different from the original through massive growth. That may be fine in the grand scheme of things, but the original character is lost.
-- While attracting “elite” how are you going to get rid of hoi polloi? If people arrive, set up camp in LW, and start discussing Jennifer Anniston’s butt and what a horrible hangover did they have today after being gloriously trashed yesterday, what are you going to do about it?
-- There is correlation between “being highly successful in real life” and “being able to avoid wasting time chattering away on the ’net”.
-- I think I would support some additional granularity to this site (subreddit style), especially if we get some population growth. Nothing like Reddit itself, of course, but the existence of two parts and two parts only seems to be an artifact from the olden days (when you went to school up the hill both ways).
-- And finally, the important question: what do you want to achieve? Is it just having more smart people around to talk to, or there’s more? In particular, with Pinky and the Brain flavour?
This is what survivorship bias looks like from the inside.