"THE CHEMICAL AGEING.....ELIMINATED ANY SIGNIFICANT ADVANTAGE OF FREEZING."
Well, can I chime in here? I'm not photochemist but I've got a couple of years of university chemistry and reducing temperature VASTLY reduces the rate at which chemical reactions will occur.
A paper that exhibits little change after a several years at 22 degrees Celcius in the dark, would, I think exhibit little change after at least as many decades in the deep freeze at negative 35 degrees Celcius.
I've used kodak paper that was stored at room temperature in opened packaging for about 15 years. It came with the first enlarger I bought about two years ago. It was a tiny bit grainier and a tiny bit less contrasty than paper that was bought brand new, but I didn't notice until I held two exact same prints side by side after they were dried.
If I really was concerned about keeping my paper fresh at the 5 or 6 decade mark....I might line the freezer with lead paper and/or use a proper lab freezer (-68 degrees below zero celcius)
I'm trying to be pretty conservative here. The fact is, I'd not be suprised to learn that paper in a deep freeze still reacted quite well after a century or more.