And speaking of the role of McCartney's bass playing in their music: in the course of reviewing all my old Sunday Night Journal pieces, I came across this review of Sgt. Pepper's Lonely Hearts Club Band, in which I made the following remark:

The single most striking thing in my revisiting of the album was the brilliance and effectiveness of the rhythm section. McCartney’s bass in particular, prominent because of its bright, rubbery tone and avoidance of the lower range, often seems to be the engine of the music, both supporting and leading.