> If you limit yourself to other old farts who still have their battered old AD&D 1e books
AD&D/1e (and other pre-5e versions) books are available in hardcopy and PDF, new, today. There's certainly a network effect benefit to 5e today, but 1e isn't limited to people with battered copies from the 1980s.
FWIW I've had more Dungeon Masters/referees for Lamentations of the Flame Princess (a modern horror-themed retroclone of the 1983 Mentzer D&D Red Box) in my home city than any other edition of D&D or any other tabletop RPG.
AD&D/1e (and other pre-5e versions) books are available in hardcopy and PDF, new, today. There's certainly a network effect benefit to 5e today, but 1e isn't limited to people with battered copies from the 1980s.