IIRC the color gradients only started to appear once PCs which could display "True-Color" (or at least "High-Color") modes were widespread enough. The original

IIRC the color gradients only started to appear once PCs which could display "True-Color" (or at least "High-Color") modes were widespread enough. The original Windows 95 definitely didn't use them yet. And the "modern flat solid color designs" still use stuff like subtle shadows and transparencies that would have been either impossible or wouldn't have looked nice in the nineties...