I'm sort of in the same boat; I've been increasingly disenchanted with most modern games. For example, Bioshock's gameplay was deeply flawed in my opinion, and its saving graces - story and setting - did not do enough to lift it into classic status in my eyes. More than that, the driving force to finish it was to see how the story would end instead of its actual gameplay as it should have been.
I have a couple of theories. First, I believe gameplay matters more as one gains more gaming experience and in general consumes more entertainment. There are good stories, art and atmosphere elsewhere - only "gameplay" is unique to games. And, when you look back, actual gameplay innovations are fewer and far between these days, at least on the PC. Sure, there may be refinement of concepts and all sorts of rehashing and remixing with a couple new spices, but it is increasingly harder to break new ground.
Another theory has to do with difficulty, which also ties into gameplay. Modern games are expensive products that are meant to be consumed from start to finish, and for this reason their difficulty tends to cater to a low denominator. Again, Bioshock is a good example of this; it rides so completely on its story that actual gameplay elements are (most likely intentionally) almost meaningless. I'd argue that anyone with half a brain and some persistence will manage to finish it, no matter how new they are to gaming. There's no danger involved. To me, it seems like the developers wanted all players to be able to finish the game at any cost. In this case, the cost was so high that it almost makes Bioshock a non-game (it's just an "interactive story.")
Time constraints are probably another reason why gaming tends to interest less as commitments increase. Most games are relatively long when compared to other forms of entertainment, even books. Most of this length has little to do with story, it's just "padding" like fights, exploration, minigames. If that "padding" is not compelling, the game feels like a waste of time or, even worse, work. (Amusingly, what people these days call "padding" is pretty much the essence of the game.) As I speculated in the second paragraph, it's possible that once one gets more gaming experience under one's belt, it is less likely that a new game manages to impress with its gameplay, and since the majority of the content is not compelling, one probably gravitates toward more compact entertainment. NWN2 is a good example of how unoriginal and repetitive gameplay killed the entire game for me.
Personally, I still play games, however single player games take much less of my time these days. Multiplayer gaming in games that actually have good gameplay is where it's at for me. This includes both computer and board games. Modern, german-type board games are fine entertainment for any gamer who can find a few real-life people to play with, and board games are still a bit more mainstream entertainment than multiplayer computer games. Multiplayer computer games can take a bit more effort to get going, but can be worth it in a group of like-minded people.
EDIT: TinCow raises some very good points. However, I'd like to contend that the "quality" of games is ultimately dependant on gameplay; aesthetics and even story are secondary. Since the pace of gameplay innovation has diminished very dramatically over the period of computer gaming, even indie gaming, it's possible that we're not going to see a dramatic resurgence of new innovation despite changes in the market. The quality games of tomorrow will most likely be well done recombinations of old formats, with very few true innovations thrown into the mix. Due to the nature of games, new games will be increasingly less appealing to longtime gaming hobbyists because most of the core mechanics will remain the same.
Here's a link to one list of innovations in gaming. You'll notice that the vast majority are from the 80's or 90's; only a couple are from this millennium. (Number 13: Reversible Time is wrong; The Killing Game Show had Reversible time, in the form of a replay, and was released in 1990)
http://www.next-gen.biz/index.php?op...1&limitstart=0
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