Yes, shadorne, Joe Cocker---I knew I was leaving out somebody! You possess musical wisdom to an unusual degree, my man, and your words, with which I agree 100%, were a pleasure to read. "Playing for the song" is the musicianship I crave, listen for in others, and employ myself. It sounds unimpressive to many, not "obvious" enough---too subtle. It takes a certain level of maturity and self-confidence to play with taste and economy (as your "it can be frightening to leave space" line acknowledges), and is what separates the men from the boys.
I first witnessed it in a drummer when I saw and heard Dewey Martin (Buffalo Springfield) live in 1969. Mitch Mitchell, Keith Moon, and Ginger Baker were my standard at the time, and it was a shock to learn there was another, very different, approach to playing drums. I had to learn how to play all over again, this time with a completely different objective---musicality, not empty virtuosity and self-congratulatory displays of pointless technique.