@SuperDicq eh, sorta yeah but also back in win95 everything was proprietary more or less, sure GNU was a thing in 80s and linux started life around 91 it didn't exactly catch on until much later, and even then it didn't exactly have GUI either and weren't oriented towards typical consumers. So back then it was like, what, a proprietary derivative of unix (HP-UX, NeXTSTEP), proprietary (classic) Mac OS, proprietary AmigaOS, BeOS or Windows. And with exception of very early amigaOS and macOS all of them look quite similar - gray/beige/brown/white/yellow background, relief effects to fake depth (white at top and left, black on bottom and right).

It all really boiled down to limitations of EGA palette and resolution. Icons had to be colorful but descriptive while fitting within 16 color palette (later improved to 256 colors), As far as pixel art goes, it would be either flat, orthographic, oblique (cabient/cavalier) or isometric, something more specific (perpective 3D) would be hard to make (at the time) and would look quite bad (see Windows 95 plus "full color" icons)

:mycomputer:

tl;dr: all GUIs at the time looked more or less the same with slightly different takes on color selection and style of icons, but it all boiled down to limitations of hardware at the time.