I'm going to de-lurk briefly to respond to this topic.
First of all, hello everyone!
I'm of the opinion that the means to grow the hobby already exists and it's in the form of the various virtual game tables (Fantasy Grounds, Map Tools, Klooge, Battlegrounds, etc.) that are available. These tools are a medium that is already familiar to many, many people in the world. They'd be using a computer to play a game which many people are already very familiar with. It'd just be a matter of saying something like, "We're going to be playing a game through the computer. It's kind of like World of Warcraft, but you can do anything you want. When you reach the end of Naxxramas and slay Kel'thuzad, he stays dead, and your actions might set off another chain of events that will require you to do something equally as heroic!"
You can easily gather people from all over the world and focus on setting up a virtual session that really highlights all the fun of D&D. The players don't have to overly focus on the rules because the virtual game tables can take care of most of them with some pre-work by the GM of course. Think of it as a gateway drug; once people have tons of fun in one session they're going to want more. They'll buy the books to be better prepared for their next session, they might visit their local game store to buy the books and learn about other games. They might tell their friends about all the fun they're having, and so on.
The mainstream already accepts people getting together over the Internet to play MMORPGs. It's not seen as anything strange. Playing D&D over the Internet would also might lessen the social stigma that is often associated with playing D&D. You're not out in the woods swinging foam swords at each other (a stereotype that somehow has become very much associated with playing D&D nowadays), you're playing games online.
I know that many people might deride playing D&D over a virtual game table isn't really playing RPGs as they're meant to be played; around a table, drinking soda, eating chips, razzing each other, etc. However, having run a few online campaigns I can say that the feeling of socialization still exists, especially if you're using a Ventrilo, Teamspeak, or Skype to communicate. No, it may not be the ideal, but who is to say that those who start playing it online won't migrate to playing in their kitchens and living rooms when they find out how much fun it is and show it to their friends?
I really feel that WotC is shooting themselves in the foot by not getting their DDI Game Table up and running as fast as possible. Heck, if they could somehow get a deal going with Blizzard and make a WoW version of the 4th Edition rules that could be played virtually on the DDI game table I think you'd see tons of interest from WoW players, both young and old, that have never tried D&D before.
My rambling two cents, sorry about the length.