As for the handwritten manuscript, I expect a man who had lived for 6000 years would have many odd idiosyncrasies. Writing music by hand does not seem so crazy in that light.
I only mentioned desktop-published music scores (which, in the real world, have been produced on composers' home computers for more than 25 years already) because no one thought of it in the 1960s, just as no one realized then that quick and easy typesetting of ordinary text in homes or offices would soon be possible.