On another note, why do all protagonists, who reincarnate/reemerge after at least 1000 years, find a world with nearly the same common sense in everyday life, just like the one they left back?
So much changes over time. 3000 years ago the Ancient Greeks had very "particular" ideas about what to do with adolescent boys and just 150 years ago you shouldn't have had any funny ideas about chasing your dreams as a woman, except your dream was to get married. In most "X000 years later"-stories the MC wake up in a world that is much like their old one, with a few "terrible and shocking" changes. Imagine Merlin waking up 1500 Years later and he finds a world depleted of real magic and filled with smartphones or 1510 years later a world emptied by in a nuclear holocaust.