I got started with 3e and have played only that and 4e so far. I'm what I would presume would be the target audience they're trying to reach with the new stuff (or at least I certainly was when 3e came out, I think. I was in adolescence). I was raised on video games, when I was younger I thought anime was bad ass. But I've found myself drawn to the older editions. Recently I got the three core 1e books used (and the Wilderness Survival Guide, for some strange reason. I think it was just super cheap on Amazon) and just today my Rules Cyclopedia arrived.
For me the appeal is the general feel the older games seem to have, or that I at least imagine them having. I've yet to actually play any of them. I think I'm going to start a monthly RC game in addition to my (mostly) weekly 4e game--1e just seemed too intimidating for me. But the idea of not needing a battle mat, and for having freeform kind of play where your ideas were what were most important, not what the books said you should do, is something I find very appealing in a post 3e world of predefined powers and strict character roles. Also for me its a reaction to things like World of Warcraft and its ilk. I kind of want something that actually feels dated. For me, as someone who missed the earlier stuff, the very fact that it seems archaic adds to the mystique and atmosphere. How I perceive the game matches with what it's about--the game seems old and mysterious, just like the forgotten ruins and dungeons and all the crazy loot my players will hopefully find.
It's hard to describe what draws me to want to play it, or at least check it out. I love 4e, and found that, as much as I like Monte Cook's ideas, I don't like 3e much at all. But there's something about everything I've read about the older editions, and the ideas of these old, forgotten worlds people played in, that really draws me towards it.
It's weird.