Specifically WRT Bach, he couldn't be used as a datapoint because his fame was not achieved in an environment in which number of publications were counted and used in hiring/promotion decisions, or had any other impact on his success. Bach was before recorded music, so most of his compositions were (I think?) heard once in his life time, by a few people who were not influential. And he didn't achieve fame until later.

Bach also has the complication that his job required him to write new music each week.

Consider Beethoven vs. Mozart. Beethoven is in the "rigorous" camp; he revised for months or years, building complex structures into his music. Mozart was not rigorous. Mozart liked to say that he didn't need to revise; he just sat down and wrote music as it came to him, "like a cow pisses." So how valuable is rigor in music?

Personally, I don't consider Mozart to be on the level of Beethoven. The Mozart that rises to the level of Beethoven, maybe his Requiem, are ones he spent more time on and did revise. (And he wrote only half of the Requieum!) But that's a minority opinion, and I'm not a music scholar at all.