But it sounds like your answer is to hope that people naturally find Pathfinder after starting with 4E (in the future that is). That's certainly one answer...I just hope for the future of Paizo that they have some sort of plan to make that transition easier. I want to make something clear: even though Pathfinder is not my game, the folks behind it are some of the nicest folks in the industry, so I wish them well.
Step 1 is getting a core book in print and available throughout all chains of distribution, from game stores to big box and independent bookstores to comic book stores. That may sound like easy work, but it's taken Paizo 3 years just to get all of its ducks in a row in this regard, and I would hazard the vast majority of companies in the industry never ever pull it off. We have managed it so far, and that's the most important first step. If you can't do this, you cannot pull this off.
Step 2 (which started over a year ago) is to build a massive shared-world organized play campaign, with thousands of gamers invested and interested in checking out what will become the official rules in about three months. This gamer network influences local gamers around the world through word of mouth, and attracts gamers to the Pathfinder brand. As you point out, long term major success involves convincing non-gamers to give us a try, but there is significantly lower-hanging fruit than that, and we have a lot of ground to cover before we start advertising on SyFy or in Maxim. Things are looking up here.
Once Steps 1 and 2 are on solid and sustainable footing, then we'll get the girlfriends and the nerd-friendly buddies and the kids and stuff.
I assume that "brand new" gamers will most likely come to the RPG hobby--to say nothing of the Pathfinder RPG itself--through Dungeons & Dragons. The brand has remarkable penetration even in the general public, on the order of something like Starbucks or even Coke. It is a Big Deal, and at many game stores and book stores, it is the Only Deal.
It is our hope and expectation that new gamers who tire of Dungeons & Dragons but don't want to move away from the genre of heroic fantasy will give Pathfinder a shot. The Pathfinder Society and to some degree even the Open Playtest help to place the Pathfinder RPG as a logical "next step" for gamers looking for something new.
Launching a successful RPG is an uncertain prospect, and it's a lot more complicated than immediately shooting for the mainstream non-gamer audience.
A lot of Pathfinder skeptics or just plain old douchebags have posted to the effect of "there are five game groups in my area, and none of them have ever even HEARD of Paizo." If this is true (and I'm certain some version of it is), that's a HELL of a lot of potential Pathfinder players who are a LOT easier to reach than your neighbor who has never ever played an RPG.
--Erik