This sort of thing happens all the time. Most people think that STP went downhill after Core (their first album). Core definately rocks the hardest of all their efforts, but if you want to look at their best song writing, dynamics, textures, etc, their best album would be Tiny Music... Songs from the Vatican Gift Shop. Their latest album #4 wasn't as good, but at the same time you can hear the tension; you can almost hear everybody thinking "oh god, lets get this done before Scott gets busted again." And compared to most of the music today #4 is very impressive. Just not up to snuff with their other three albums.

And actually, Primus gets the same thing because they didn't put out seven versions of Frizzle Fry.

It's basic human nature to want things to stay the same; to want everything to be just where you left it. Many people can't cope with change, and don't have the vision or open mind to let artists do what they need to do.