Watching, I was struck by how funny it is, that in modern small combo jazz, the horn player often sits there and basically does nothing for what amounts to nearly half of the concert.
The piano, drum, and bass players play the whole night, but the horn player plays during the head and his solos and then just sits out the rest of the concert.
Related, listening to early jazz, Armstrong, Oliver, Bechet, I’ve been paying attention to how the clarinet interacts with the ensemble. It seems like the clarinet is most closely allied with the banjo. While the brass, piano, and drums play mostly on the beat, the clarinet & banjo play contrapuntally and interstitially.
While the horns play the main theme or motif, the clarinet will often play against the theme, or after it, or during breaks in the music. Sort of like the clarinet player is commenting on the theme.
Similarly, in early small combo jazz, the horns don’t sit out, they act as part of the rhythm section when they are not actively soloing.
It’s funny that that custom seems to have been lost in much of modern jazz.