Bach as part of his job had to write a great deal of music, several pieces a week and by piece I don't mean a singular piece but rather somethin like a concerto, consisting of either three of four movements. Thus he had to write 6-7 independent pieces of music a week.
Do you think he only wrote music three times a week? Tchaikovsky would spend entire days for months on end working on music. Or is the process of writing music so much higher then the listening to it? Which seems absurd because music is written to be heard, not written to be written.