Engine vs Game. I think another issue is the constant pressure to enhance the engine - display and sound have highly increased complexity. Did I really need the latest engine to enjoy the game?? - maybe not.
Indie game publisher have begun to explore this and we may see several classics evolve in this space as they experiment with gameplay using older more stable engines.
I have the feeling that the internet has changed the economics and publishers are doing what they have to. Perhaps years ago there were games which focused on play and not on "wow". This was probably due to the fact that patches were much harder to deliver and so there was more testing before delivery, but then the publishers discovered the consumer as the free beta tester and we are where we are today. However, they are shooting themselves in the collective foot..
Due to this change (using customers as beta testers), customers are changing their buying habits. I believe there is a growing group of gamers who will not under ANY circumstances purchase a game that does not have good reviews and positive forum content about playability. Add to that the thousands of prospective buyers with slightly older hardware who will wait until they have a stronger platform and you end up with fewer customers at launch (thank you, beta testers!).
Frankly, I haven't purchased a game within the first 6 months of launch in the current century... and I build my own PCs (thanks, NewEgg, TigerDirect, etc). Why? <1> requirements, I want to upgrade to support fluid play, <2> bugs and glitches, I want to avoid buggy messes which need 6 months to get the patches written, <3> DRM - openly declared and stealth, I will not buy crippled, intrusive, buggy programs, <4> poor playability, my game time is too limited to waste on an "average" game so I wait for comment on the forums to swell and, finally <5> competition, there are so many really good games already available and beta tested by "at launch" buyers so I do not need to purchase something which is rushed, buggy, untested, unplayable, etc.