Neutral Grounds Robinsons Galleria is currently on a moving sale (don't fret, they're simply moving to the next week). RPG books are like 50% off while the cash-cow items (i.e. miniatures) are going for 10% off.
Just talked with the owner and I confirmed my suspicions: RPG supplements aren't selling (or rather certain supplements do sell... it's simply hard to predict which will and which won't). The Core D&D books have been doing well but they've essentially stopped importing supplements. D&D Miniatures, on the other hand, are a different matter. So it's come to the point where they've stopped importing D&D books but keep on acquiring D&D Miniatures. Which isn't really a surprise to me. What is, however, is the fact that they haven't been cashing in on WotC's other cash cow: Dungeon Tiles (at least according to my theory). Have no fear however as Neutral Grounds will be giving the product a shot.