Bands aren't soft, they know when they're finished, what's good, mediocre etc. Often they're tied to album deals so need to stick anything out, as a money making exercise. You can't even compare Definitely Maybe to something like Heathen Chemistry.

My lad who's 19 and all his mates love them but they tends to just have the first couple of albums on, so it's not just us getting old or being miserable arses, the kids are doing the same.