Sony doesn't care about the PS2 because there really isn't much of a market for it anymore. The 'core' segment of the PS2 audience has moved on to the PS3, Xbox 360 and to a lesser extent the current generation of PC gaming. This segment places a lot of importance on graphics. The 'casual' segment on the PS2 has moved towards the Wii. To them, the motion controls are much more fresh than traditional gamepad gameplay. So really, the PS2 has nothing except for what's left of the value market (gamers who can't afford a Wii or Xbox 360 Arcade but can afford a PS2 Slim) and the hardcores who may already have current gen systems but still want to play PS2 games.
Also it's difficult for most gamers to be excited about old software. This is why you'll find that even the core gamers (well those ones who don't hate Nintendo. There are millions of self-proclaimed hardcore gamers who wouldn't even touch a Wii or DS) would sooner play a new DS game than play an old but more graphically impressive PS2 game.
