It's amazing how many times "nostalgia" is the motivation automatically assumed when discussing classic editions.
I think you misunderstood me. (Which is not to say you'll agree with me even if you do understand me.)
I'm not saying that people like the old games because of nostalgia. Heck, if I wanted to run or play in a non-4e D&D game I'd be tempted to go AD&D/OSRIC ahead of 3E.
But what puzzles me is why people care whether its WotC or someone else who's publishing the OSRIC rules, new OSRIC adventures, etc etc. Nostalgia seemed a possible explanation for
that.
I was also suggesting that nostalgia might be a reason why people want to (re-)purchase Vault of the Drow, the Slave Lords etc. Raven Crowking has given an alternative reason - new copies to replace old worn out copies.
The weird thing to me is that WotC has all this IP that they could sell to people who may not be all that thrilled with 4e's sparse setting philosophy
Because I've always been happy to prepare my own setting stuff, and/or to cobble together bits or pieces of whatever I've got on my shelf (D&D's pantheon meets Palladium's pantheon meet's 1st ed Deities & Demigods meets . . .), maybe I personally don't feel the force of this. Especially because quite a bit of this stuff is on my shelf (mostly but not always picked up second hand from my local game store). I can see how others might feel differently.
My own hypothesis is that WotC are sitting on their IP because they believe that by selling it, even if the proceeds of sale are greater than the cost of hosting and processing sales, they will dilute their brand and therefore ultimately cost themselves more sales. I don't know if this is true. If I read him correctly, I believe that DannyAlcatraz thinks it's false.
But WotC would hardly be the only company that sits on its IP. That's the way of things in a world in which cultural production is privatised. (My collection of Rolemaster materials is incomplete, for example, because some of my stuff was lent out and not returned, and other stuff I never got back in the day, and now you can't get it at all. This is just the way of the modern world, I think.)