Yaomon, I hope you don't mind me speculating a bit, since I find it interesting to think about.. I think it's more a matter of expectation/adaptation- where you have variety of content(games), some will provide more to digest than others. If you're consuming a lot, then when a lesser game is crossed it doesn't fill you as much, so there is less satisfying feeling regardless of what it is.
I think this also leads to the suggested issue of short attention span- if you've adapted to consume more, you'll seek out more, so whatever is less appears unappealing. It also sounds like it might also relate to an addiction, or an acquired behavioral pattern.