I've got a carton of 700X19-26 Presta tubes, most date from 1975 to 1983 or thereabouts. They work fine, boxes fall apart... dried out glue... but the tubes look and feel like new.
Of course, I keep them in the house. I've an attic bedroom that's become a sort of bicycle workshop. It's dry, climate controlled, and well away from ozone producing motors. (Fans, washing machines, compressors. All of these will eventually ruin rubber .) Plus, lugging bikes up & down the dark, narrow stairs builds character.