In that period 3d accelerators were basically capable of running Quake and not much else. Traditional demo effects that relied on reading the backbuffer (even to just do some basic postprocessing) were either unavailable or had to have bespoke implementations per card. There were no shaders to speak of, and so on.
For me that really killed demoscene innovation for a while, and a lot of demos basically consisted of a bunch of alpha-blended layers for a while.
Nowadays, though, I'd say the scene is probably doing pretty well even though it's arguably even more niche than it used to be. Oh well.
Ahh the legendary glBlendFunc(GL_ONE, GL_ONE) era. The most underrated of demoscene styles!
The transition was definitely odd. What brought it around for me was when fr-08 was released and the broader scene realized what _could_ be done with procedural generation and whatnot.
If you've never seen the Making Of video that was released a while back, someone has been kind enough to add English subs:
https://www.youtube.com/watch?v=3S-2zGkr7vw
Second Reality is the single most amazing piece of art for me. Nothing else holds as much emotion as that demo. To see behind the curtain is like, I imagine, for someone else to watch Van Gogh actually painting.
"Unreal ][ Main theme" is still on my main playlist on my phone, and I've yet to go through the thousands of .XM files I just grabbed off some FTP site back in the day. The MOD community is a related rabbit hole one could get lost in . . .
4 kilobytes!