As for that decond part- 3D being easier and so on, have you ever thought how much time you need to model, texture and animate even a simple 3D character? I daresay a spriter could achieve great results in pretty much the same time and on a lower budget!
Plus there is also a ecological loop between the manufacturers and developers. Most of them advertise ATI or NVIDIA or INTEL at intros of games. So 2D games changed dimension by the natural selection =)
With the flash revolution, 2D games morphed into vectors and that really sucks. I know, we are in 2009 and it would be a shame if we were playing still 2D game. Maybe, soon a virtual reality machine will pop from somewhere.
Only brilliant 3D ultrarealistic graphics doesn't make a game beautiful. A game must also have a spirit. You know, while playing Yahtzee's games, I feel I'm going to shit in my pants. Does it use Source engine or something? Todays game developers must think that way and maybe invent some different genres or make it unique. Because it's getting too repetitive.