Rok, with all of the other jazz musicians I've followed, all of them changed, but in ways I could relate to. Miles was an "enigma", although staying relevant/ popular with the current generation was important to him. While I didn't know Miles personally, I knew his brother, and we both thought the same things about Miles new music; of course this had nothing to do with how much he loved Miles, or how much Miles loved him.
I've got Miles CD's that get played when I can't remember what they sounded like, and they come out of the player as fast as they went in. The last time I saw a live performance of Miles, he looked like Sinbad out of "Arabian Nights". There was an unknown sax player I don't remember but he really sounded good. I was deep into the sax man's solo when Miles blurted in sounding like an ardvark fart. It's for sure he never lost his ability to select the best new talent, but his ego got in the way of the music. He never would have done that when him and Trane were together, although he said Trane played too long.
In regard to his changes, while he lost old audiences, he always gained even bigger new one's, which certainly helped his bottom line; that's what I call "upwards failure". I call em like I see em.
By the way, nobody has mentioned "Quincy Jones"; he's a musician that was always changing, but each change brought about a new and interesting sound, I'm going to get into Quincy next.
Enjoy the music.