All my railing about downbeats should not be taken for an anti-jazz stance - quite the contrary.
The best jazz groups do not play successive identical downbeats - if you pay careful attention you will hear that. In fact, one of the attributes of a jazz combo is the separation of the strictly rhythmic character of the beat (the drums) from its tonal aspect (the bass). This is a modern-day rearrangement of the Baroque continuo, in which a cello or bassoon played the bass "melody" doubled also on harpsichord, organ, or lute.
The trouble arises when one person tries to combine the two functions. Just because it is intended to be played by a single player, piano repertoire does not simplify the connection between tone and time. It's just that it's harder for one person to activate two impulses at the same time. In the struggle the more obvious element always wins, i.e., the beat.
That is probably why jazz musicians who long to play Brahms and Debussy (and I have been privileged to work with quite a few who meet that description) have so much trouble "getting" it.
A fascinating thing to ponder.
