I agree with the point about lack of polish and bugs. I used to buy computer games the day they were released - but I've been burned so many times now (Battlefield: Vietnam being the latest), that I wait for months to read reviews and let the patches come. As a result, sometimes I never get around to the game - lost sales for them.
I think it's a combo of buggy, rushed software and a complete lack of originality in recent years. I can only think of *one* PC game I've heard about recently where I get excited about the concept: Evil Genius. Everything else recently has felt derivative and worse, consolized (DX:IW anyone?).
I'm actually replaying Planescape: Torment right now, and I'm still in awe of the sophistication and maturity of the dialogue. To me, PS:T stands as the perfect combination of original concept and mature execution. Of course, like so many other sophisticated, mature games in recent years (NOLF, NOLF 2, System Shock 2), it tanked at the box office.
I suppose in one sense, WE are to blame, in that the very games that are original and sophisticated have almost universally done very poorly in sales.
Don't know the answer - but I think there's a very real chance that PC gaming, as we knew it, is dead. I just hope I'm wrong.