There was a lot of one-upsmanship at the time. People did it because it was hard. When it wasn't difficult to do anymore, they stopped because it wasn't actually good clean design.

Also, early on, there was an idea that cyberspace should resemble meatspace so the meats don't get confused. That's no longer much of a concern.

Remember motiongerm and the whole sleek 60fps flash design thingamabob? Bespoke interfaces everywhere