maybe for the rear glass. windshields get pitted and scratched from road dirt over time and you can find yourself in a dangerous whiteout when facing the sun. i had a bad experience with an old 65 mustang windshield once.
I can't imagine wanting to reinstall old faded fuzzy glass, front and rear, think there a market for this/
There is no market for garbage.
Glass: Every car came with a full set. Windshields get replaced all the time. Coupe rear windows are not worth the effort to remove them. Coupe door glass is what is thrown away to make a good door shell shippable.
NICE CLEAN SCRATCH FREE convertible and fastack door glass has a market. Ditto with the fastback rear glass, but it is almost impossible to ship.
I sold a bunch of glass from Unique Performance, and was happy to get it out of my garage. Low market for the stuff.