If you search for “why don’t we build beautiful buildings any more” or any similar combination of terms you’ll get a great many articles, essays, blog posts, and YouTube videos on the subject. (Ross Douthat’s column is an especially good one.) Most of them agree with the question’s premise, but there are some who don’t, some who say that modern architecture doesn’t reject beauty so much as offer an alternative kind of beauty. Okay. But I’d suggest a little experiment.
1. Look at any 20th- or 21st-century building that you admire.
2. Look at the octagon tower of Ely Cathedral:
Click each image for a larger version.