China and Russia are big on software pirating. Cartriges can be pirated, but not as easily. With hackers leading the software developers, super harsh restrictions on PC games like what they did to WoW, Spore, SC2, Settlers, is causing a backlash from normal people that don't want to play a game online, so lack of interest in PC game sales means less developer money. Consoles are low graphics, low content, low functions, and higher 1-time price, so it's just business to watch PC sales fail.
1. Killing resales of Console disks -DRM doesn't stop pirates, doesn't even slow them down. It does hinder resale. More recently it requires people in the same household to buy separate copies to play one game.
2. Polluting the PC gaming environment so badly gamers buy a console. - Hey you want this new game? Well you already know the PC version will be released later, maybe even at the console price, and it will be dumbed down for LCD players who had to use a gamepad, and no matter how much we say it isn't, it will be a port of the console version with maybe a couple of semi-patches. Wouldn't it just be easier for you to buy a console?
Not only console controller aiming also console space limitations on dialogue and textures. Characters say the same things over and over again and huge cities become a labyrinth of sameness. LCD becomes "lowest console denominator" no advantage to a blu-ray writer.
Windows is losing ground to mobile gaming too. 16 billion spent last year on phones and tablets.