Maybe I'm wrong, but it feels like modern architecture is about cutting labor and material costs as much as possible. Old architecture had craftsmen put a lot of time into things like smooth plaster walls, molding, wainscoting, herringbone floors, and decorative exteriors. Modern architecture is founded on the principal of hiring the cheapest labor possible to throw up the cheapest drywall available and covering it up with texture to hide the low quality - then charging as much as buildings using the older, higher quality methods.

Of course modern architecture is just going to look bland, generic, and low quality compared to old architecture - there's only about 10% the effort put into it.