Growing the Hobby: Retention over recruitment?

Dipping my toe in the water here - this month's Blog Carnival seems pretty appropriate, so here goes:

I've seen some great ideas for getting people in by getting out there and running great intro games, and being the inspiring DM/GM who grabs - and keeps - players' attention. It's the second point that really got me thinking...



I was the newbie, freshly added to a friend's 4E D&D campaign and fifth PC in the party. Then I got bitten by the DM bug, wanted to try new systems... and we've lost two players to disinterest, which is quite possibly at least partially my fault.

However, it seems we've lost the "powergamers" and kept the "roleplayers" - the ones whose 4E characters did the non-killy stuff (whether through non-minmaxed stats, intentional cowardice, or appalling dice luck) and got involved in the story instead.
The others still wargame together, and with us, and would probably set up their own dungeoncrawling group too - so maybe the loss isn't a loss after all.

I've tried getting people involved, and it seems that non-gamers are hesitant - because we're nerdy, maybe, or because we're a difficult crowd, allegedly. I'd love to see more people get involved in gaming, but it seems like you can't please all the players all the time. I'm not interested in the technology, or the gamer bling, because I don't think it's the issue - I think I need to work out what my players (old and new) want to get out of their game, and make sure as GM, or playing someone else's, that I put it in.

Maybe I've been worrying too much about finding good systems, and not enough about making involving worlds? Or is there more to it than that? If I can get the players hooked, will they bring in new blood by themselves?