The problem is that UX is mixed with and influenced heavily by (often simply dominated by) design, and design comes from the creative arts world. The creative arts have, since the end of the Edwardian period, and especially since WW2, stressed stripped down minimalism and originality. A lot of this comes from an innate hatred of the bourgeoisie, some of it is simply fundamentally anti-humanist Platonsim.

It worked fairly well for a lot of industrial design, but has been a disaster for the built environment and, we are learning, software.