I've more frequently seen price drops on new drives than on blank BD media. Maybe something to do with lower adoption rates of the technology, coupled with companies trying to recoup their R&D costs and still turn a profit. People will only have to buy one drive, so that's a non-factor in comparison to the number of discs they must buy to use with the drive.
I imagine it to be sort of like buying ink for an inkjet printer, with the distinction that it's not HP ink for an HP printer or Epson ink in an Epson printer; instead, it's Philips and Sony pushing out the licensing costs on something much lower in shipping volume than CD & DVD. Combined with the higher cost of materials for BD (probably not worth the substantial price difference relative to the older formats, but still...), it means peopl companies aren't really trying to push the price down when it comes to consumers.
Gotta keep that premium technology at a premium price!