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.
A meta note, inspired both by Proust and by this book about Proust: after reading a book, when you're making notes, don't refer to the book; just write down the most interesting things that come to mind. This is a better way of digging out what actually struck you about the book; as soon as you have the book to reference, you will start looking up the bits you "should" write about, and end up aiming at comprehensiveness rather than interestingness. Your actual criterion should be whatever interested you. Later, you can fill in quotations & references.