I didn't misinterpret your post as implying 
interest in collecting restored, American 
animation series cels, but if you want to know 
about longevity for 60 years, Disney is the best 
reference point.  

The cels I'm referring to are unrestored, 
untrimmed, non-repro, original production cels 
that I own, including a vintage Atom and vintage 
Disney. FWIW, the Atom is in better condition, 
but so was I when I was half as old.