I didn’t really answer your question about the correlation between genius and chronological time.
A genius in art is someone who stay in our collective memory as a representative of his era.
The history of art is parallel and perpendicular to the story of science whose two are part of the history of consciousness which we can read in the history of language itself...
See Owen Barfield : history in english words...
Monteverdi is a genius because he manifested his era on another level inventing opera ...
I dont like many opera...
I like madrigals a lot especially Gesualdo and the 8th book of Monteverdi...
Art is not about "taste" which are only an expression of our own personal biased history... Art is about some truth of an era and his link to universal truth...
I recommend Jean Gebser masterpiece book about consciousness history " the ever present origin" ...
If you dont fall out of your chair i will pay the book price...