I'd say things, ideas, opportunities and ways of being/thinking are even broader now than they were than when I was a teenager in the 90s.
But yes, you are right. Back in late 90's/early 00's Linux and Unix desktop were trully different and unique. Fluxbox had zillions of different themes. 3D, black, retro, flat-ish, metal-ish, Java styled, Gnome styled, KDE-alike, Gaudi, childish, Bohemian, alien looking... every style was fine for anyone.
Ditto witht the icons. One day I felt technical and I switched into the Slick theme being "workstation/highend" themed with a gray color scheme, and the next day I felt nice and cheerful and switched into Noia with a blue Keramik theme.
Now everything looks bland, flat and everyone looks afraid on having an style.
I can't quite understand how "Linux GUI, make it look how you want! Personalized OS!" became "Linux - this one unchangably bland tablet UI on your desktop!"
I know that other WM/DM exist, but Gnome is incredibly popular, often the default, and was so close to being what people saw as the ideal Desktop.
Take a look at for example the youtube creator dashboard for an established creator, how it directly compares your videos against each other, trying and pushing you to get more numbers, entirely uncaring for anything other than eyeballs.