Interesting thoughts...I think rake is a factor for everyone, not just the tightwads, but I agree it is way down the list, action being number one.
So if you are a poker site trying to entice action by offering lower rake, then you had better be competitive in all other areas as well (ie. software speed and reliability, customer service, user-friendliness, layout, etc.) or you won't have a chance.
The place I see a real opportunity for low rake to make a difference is heads-up games. Even at 50c per game at levels like 10-20 say, that's over $100 per hour being raked off since you easily get 200 hands per hour. Just like in online chess, there is something about head-to-head combat that is enticing in itself and a good player usually doesn't mind playing against another good player because the ego element is more important than the money element. But if you are faced with paying $50 per hour each just for the privilege of using the website, then it kind of makes things undesirable. Imagine paying those kinds of fees for online chess!? OK, poker offers banking services that chess does not but is it really that expensive!? I think heads-up rakes are highway robbery as they are now and I think they could be reduced to as little as 10c per hand and the sites would still make nice profits. The opportunity to play heads-up on-line at reasonable prices would really make things exciting IMO and it is a shame that no site has taken this route as of yet. As for the future, though, I'm still hopeful.