Does anyone know if WotC has done a big buyback? It almost seems like someone has been scouring the bookstores methodically, snatching up everything that would suggest an older edition ever existed.
I can't speak for other places, but I ended up talking with several local game store owners in my neck of the woods. From what I've been able to piece together, a fairly self-reinforcing cycle kicked in about the same time they announced 4e:
1) 4e announced, fanbase is split as some embrace the expansion, others see possible writing on wall and begin buying 3.5e stuff where they can. Some hobby stores begin discounting 3.5e in order to clear out "old inventory".
2) As more people begin to grab 3.5 stuff, sales in local stores of said increase, outpacing 4e sales noticeably. Stores put in restock orders to local distributors. Lower margin per item is compensated by higher volume sales, so local stores wish to keep items in stock as much as possible.
3) WoTC notices that 3.5 demand is higher than 4e. They then conduct a buyback at the distributor level (this is what happened in my neghborhood. WoTC bought back, at almost retail IIRC, all of their own 3.5e product). Distributors inform local stores that they have no more WoTC stock in inventory and will not be receiving more.
4) Locals discover 3.5 isn't getting restocked, many core books are cleaned out and several secondary markets are also cleaned.
End result: 3.5e stuff is virtually gone except for several niche stores that only stocked it as a secondary product (I've found myself hitting Chapters stores, Goth clothing and miscellaneous stores, and other out of the way locations to pick up various 3.5 stuff).