Well that's true to a large extent, but art photography is still a business, and a vital industry to the people that are in it. Large format too, is a medium that is more economical to do with film than digital. And then there's the movie industry...

I guess glass plates would basically be a niche within a niche.

What they really need to do is create a panchromatic liquid emulsion! Then we could easily coat our own glass.