Could the poorish sales be due to games being released on all major platforms these days? I mean most games are actually playable on consoles nowadays (referring to first person shooters mainly) and when you can get e.g. the XB360 Arcade for a fraction of the price of a comparable PC, it's no wonder that the sales start looking poor. I have no doubts that piracy is a becoming a huge problem (like it was with the Amiga) and if someone doesn't come up with something to stop it (or at least slow it down) the publishers will start to pour more money to the console versions and leave the "leftovers" to the PC conversions.
Just my 2c.
Cheers,
Nick