Which band is this?

Their first album was raw but with clear potential.

The clear development shown in the second album brought them a wider fanbase.

Their classic third and fourth albums, where all their influences merged with their own voice to produce something wonderful. These are the songs the fans want to hear even now.

The fifth album. More experimental. Diversification. They'd grown tired of what they were playing before, but somehow that tiredness is showing in the music.

The sixth album and beyond. Where are the great riffs, the melodies and solos?

Or is this the fate of all bands? And if so, why?

In my restless dreams...
I see that town.
Silent Hill.
You promised you'd take me there again someday.
But you never did.

Well, I'm alone there now.
In our 'special place'...
Waiting for you.

Quote by Alpha_Wolf

Jebus, that's f-ing disturbing, looks like a mask at least.

Anyway, Yeah TS that is the curve of a lot of bands, sadly. Then there's bands that change it up a bit every album but still have a similar personality to all the songs, like Neil Young or Jack White.
Most bands do their best work in the first 3 albums. From what I've seen, they either run out of ideas as they don't have enough composers to diversify further, or they just get too rich and complacent and start to suck. Middle age screws everything, including great bands
Lots of rock artists kind of run out of steam by their late 20's because rock music is more about being able to convey the right attitude than it is about being an articulate musician. Once they stop being young, dumb, and full of cum, they generally stop being able to bring the attitude that defined their early sound that made them popular, and instead of trying to do something different which is more in sync with who they've become as people, they just keep making the same records over and over again because that's what they're comfortable with.

There are several bands that I believe have remained consistent over a period of several decades (for example, King Crimson, etc.) but it's a lot rarer in rock music than it is in Jazz or especially Classical music. Most of the great composers didn't write their most famous works until they were well advanced in years.
hmm.... this seems to describe a certain boring thrash band turned boring alt rock band turned boring thrash nostalgia act. I can't remember the name.... Metalisomething.

Most bands run out of steam well before their fifth album. I think Pantera is a pretty good example of the typical rock band career (for purposes of this i'll be excluding their butt rock era): Strong debut, awesome follow up, then just release subsequent albums that are sonic clones of your magnum opus until people realize you've become stale and boring and stop giving a shit.