If few are collecting, there is no supply! Then when they become nostalgic in 15-30 years-the prices go through the roof. Like the old baseball cards no one kept or their mom threw out. No supply=high prices.
Doesn't mean there aren't any out there, just that there is no demand. The stuff you mentioned fits this category, all right. Back when I was collecting comic books I had stuff from the thirties and forties, funny animal stuff that I couldn't even sell because there were plenty of them, just no demand whatsoever. It IS a good time to buy stuff now, if you've got the money, bad time to sell just about anything that there isn't a real high demand for.