Kinda, but there were definitely far-cheaper options for materials in the early 20th century than ornamental sorts of stone like marble, they could definitely make much cheaper doors than big-ass heavy metal ones that'd still last at least as long as cheap modern doors, and they could make stick-built structures instead of e.g. heavy stone or brick buildings back then, and they often did—far nicer in some ways than ours, but that part of our slide in quality has the excuse that there simply isn't any lumber as good as what they used, anymore, unless you tear it out of an old building—but instead they chose to spend quite a bit more to make serious institutional buildings feel serious. Even for something as mundane as a post office or library in a little nowheresville coal town.

I was curious how expensive marble actually was, so this is my attempt at looking at historical archives:

Tiles were ~1" thick: https://archive.org/details/TheBookOfVermontMarbleAReference...

Using an 1889 price book, it cost ~$0.25/ft2 of tile. Add $0.70/ft3 for shipping to St Louis, which is $0.06/ft2 of tile @ 1" thick. That's ~$0.30/ft2 total in materials. https://archive.org/details/pricelistrutland00verm/page/16/m...

50' x 50' x 10' building, (floor:(50 x 50) + walls:(4 x 50 x 10)) = 4.5k ft2, which @ $0.30/ft2 is $1,350 of marble.

For comparison,

- Average annual wages look like ~$700: https://babel.hathitrust.org/cgi/pt?id=mdp.39015002738212&vi... - A 50'x50' 2 story house was probably $4-5k: https://archive.org/details/gfbarber1905/page/n20/mode/1up

So adding the marble interiors may have been 25-33% of the price of a house. If the average US house today is $400k, then that's $100-130k for the marble interior.