In my experience, the "first version is the 'best' version" thing holds true for CLASSICAL music much more than it does for JAZZ. In the classical world, people even refer to "imprinting" on a specific version of given work. In my case, one example of "imprinting": The very first version of Brahms' Second Symphony that I heard was Bruno Walter's "Indian Summer" interpretation with the Columbia SO. It's still one of my very favorite recordings -- of any music.
Again, speaking only for myself, I can't think of any comparable analogue in jazz. When I hear people other than Miles or Coltrane play, say "All Blues" from KoB or a piece from A Love Supreme, it's supposed to be different. There is no theoretical Platonic ideal in jazz like there is classical music. The fact that there is no score in jazz (like there is in classical music) means that jazz is performer-centric, rather than composer-centric. (Of course, this isn't absolute. I'm speaking in relative terms.)
BTW, this way of thinking about these things might just be my way of making sense of it. Others may feel very differently!