You see the same thing in literature, where modernism has crowded out of other styles. As one example, you see way less description today than in older books.

I'm not a hater on modernism -- I like stripped down literature and architecture (though I wish concrete buildings were cleaned more regularly). But there does seem to be some truth in this idea that "the elite critics" have dominated these fields, resulting in the production of art (and buildings) that are broadly unpopular. I think the overriding goal of these critics is avoiding kitsch, which they see in classical forms.