The grunge revolution is one of the swiftest and most severe cultural changes I've ever witnessed in my four-and-a-half decades. You're so right, the hair bands were here one day, and poof.....gone the next.
What's odd to me about what I mentioned is that in a lot of cases, even when the bands stick around with less notoriety, they just don't seem to have a handle on their earlier vibe even when they clearly try. Referencing the hair bands again for an example, I picked up a Poison album around 2002 out of curiosity. They clearly were still aiming for the same thing they did in the 80's, but it just wasn't happening. It's like, they knew the formula, but the formula required the actual 80's to be present in order for it to work. It's a weird thing, because those bands can still perform their old material and it's just as good, so I know it's not a matter of my tastes moving on. They just can't write new stuff that quite sounds the same.
I also think your point about the catch-22 of audience expectations is right on. It may last for a few albums instead of just the first one, but after a while it does seem like audiences either slip into the "Oh, this is the same thing they've been doing....meh" category, or the "Oh, they changed their sound and I liked how they used to sound" category. Acts that maintained a good quality and good a fanbase over a longer time-span of multiple albums are probably rare, and they have my respect.
