I have sometimes wondered whether our unconscious motive for doing so much useless work is to show that if we cannot make things work properly we can at least make them presentable.
"A builder who hides any part of the building frame, abandons the only permissible and, at the same time, the most beautiful embellishment of architecture. The one that hides a loadbearing column makes an error. The one who builds a false column commits a crime."
Contemporary architects are, however, increasingly engaging with ornamentation. The zenith was Grayson Perry and Charles Holland of FAT’s fairytale House for Essex (p64), but it does not serve as an indicator because the involvement of an artist has allowed an enhanced engagement with ornament until it surpasses mere decoration and becomes embodied in the architecture in a way that architects do not allow themselves to do. Think of FAT’s old work: the ornament is all contained within a surface - a facade - which allowed them to separate out the (Modernist) architecture from the (kitsch) superficiality of the elevation. Like Venturi before them, their ornament allowed them to have their ornamentally iced cake - and eat the Minimal Modernist sponge underneath.
As a practical matter, I think it's easier to see ugliness than to imagine beauty. Most of the people who've made beautiful things seem to have done it by fixing something that they thought ugly. Great work usually seems to happen because someone sees something and thinks, I could do better than that.