First off I recognize my question might be flawed, as there might be recent examples I'm not aware of (and it's also being asked from an American's view), and there might be other subs better suited for this question, but...
I feel like we never see current, new examples of large buildings built in the styles you see in older construction from urban American centers at the turn of the turn of the century like New York City. The ornate details and the beautiful designs, I feel like these styles are more or less extinct today.
Is this purely because of changes in taste? Did modern safety regulations make these building styles too expensive? Did these styles become too expensive because of changes in labor and material costs? Are we just cheap and boring now?
Edit 2: Just realized my phone auto corrected and destroyed my title. Gotta love mobile.
The level of craftmanship that created carved stone ornament and elaborate masonry is no longer available or is outrageously expensive. When such skills are needed for buildings being restored or cathedrals being completed, elaborate measures have to be taken, including bringing craftsmen out of retirement and setting up apprenticeship programs.
In addition, architects since the 1920s have felt strongly that buildings should be of their time, reflecting the social and political conditions under which they were created, and using the most efficient technology of the era. So few architects would want to design a truly historicist building, few developers would want to pay for one, and few contractors could properly construct one. In categories like luxury residential, where there's demand for the historic forms and ornament, modern compromise solutions include certain large, impressive elements—but on buildings that use today's technology and materials. Occasionally, universities or other public clients will pay to create a truly historicist building, and historic styles are proudly taught at Notre Dame’s school of architecture. “Pretend Deco” buildings are not uncommon; new residential towers in New York and (under construction in) Chicago are in that style, as were several office buildings built in the 1980s and 1990s.
At the time, Art Deco was merely known as Moderne or “modern,” precisely because it was ahistorical and reflected the contemporary world. But—just like the buildings being designed today—buildings of the 1920s and 1930s impressed with their shape, their extensive display of new materials, or impressive applied artworks, whether bas-relief panels or mosaics.