I think this is common knowledge and can be found in a lot of music history books. He was essentially the culmination of a contrapuntal tradition, after which people started writing more homophonic music.

Some supporting evidence might be:

1) He was basically forgotten after his death until being rediscovered by Mendelssohn (https://www.loc.gov/item/ihas.200156436/). Googling this "fact," I also found this somewhat dissenting post: https://notanothermusichistorycliche.blogspot.com/2016/06/ho....

2) I recall remarks from his sons somewhere about their father being old-fashioned, though I can't find them right now.

Re: GEB, I can't speak to hofstadter's psychology, sorry.