As far as D&D not being a cheap hobby, I strongly disagree. Oh sure, you CAN spend all sorts of money on D&D, but, it's not required. You can also go out and buy that 50 inch plasma TV for your Wii, but, it's not required either. Those are just extras.
The only required material is the Core 3 and some dice. That's it. You can play D&D for about 200 bucks. There are very, very few hobbies that you can do that with. Never mind video gaming, look at other hobbies like model trains, or RC airplanes, camping. Try going camping for 200 bucks. There's a group activity that you can do every week. Good luck doing it for that money though. Try playing any team sport for 200 bucks a year. Might get you a pair of skates, but no pads.
Yes, D&D can be expensive. But, that's an option, not a requirement. Nothing forces you to buy the latest supplement. That you choose to is no different than the hobbyist who buys the latest goodies for whatever hobby strikes his or her fancy. It's not needed.