the disappointment/bordome/fatiguè-wave (whatever you wanna call it) is some kind of phenomenon with multiple factors coming into play. you see, games have actually never been better from a presentation point of view, all the possibilties with motion capturing, voice acting, video sequences, 3D, all the technique, holy moly namsayin?
What seems to bother people most is the fact that games have become dull, from a content (challenging) point of view. And while I certainly agree there are of course exceptions which make things bearable.

Yes the gaming industry has become a huge business, multimillion dollarssss and what not, and often you have big companies taking advantage of the customers and in general deliver some 08/15 shooting game that has been done 10x before. Innovation is hard to come by. Look for "Remedy", lol, they are very innovative (created max payne and alan wake), they deliver "deep" entertainment with the certain touch to it, if you can undestand. like breaking bad or the wire on tv, there are games that just stand out, which show that games actually still can deliver and be different and or innovative.

these days there's a certain pattern publishers follow cause they know the mass will go with it. have a game that looks awesome, a mediocre story, with a lot of shooting, have 2 or 3 dlc's ready, and don't forget to advertise it.

edit: oh men that post wasn't finished at all, I hit the wrong reply button. (:

what I am trying to say was that yes, the gaming industry should be more creative and so on, but also it's the environment that makes them. If people buy shooter xy pt: III and don't question its mediocrity at all publishers won't feel the need to deliver something fresh.