>>2006517>>2006573Different Anon.
Astro Boy 1963
Sally the Witch (first "magical girl") 1966
Space Battleship Yamato 1974
Gundam 1979
Cowboy Bebop 1998
They say "the golden age of SF" is 13. That is, whatever year YOU were 13.
By analogy then, "old school anime" is anything older than you are. ;)