At the end of Bach's career he was considered old fashioned because his music was based on counter melodies (counterpoint) and the "contemporary" music was leaning towards a more dominant single melody supported by accompaniment. He might not have made the billboard hot 100 there at the end.
He was a stick-in-the-mud. I used to constantly tell him - "Joe, man, you've got to lose the counterpoint thing and get hip with some single melodies!"
Would he listen?
NO! 