I agree with most of your assessment. Where we differ in opinion is who Jim is and why Kadary left. Kadary has, very reasonable, NBA hopes. Sitting behind and splitting minutes for another year with Joe is absolutely an issue for his future. He should have been starting and playing 28-30 MPG. That didn't happen. It didn't even happen when Joe was recovering from being sick. I would take issue with that if I were Kadary. It was very clear to him that he was not going to pass Joe in the pecking order and it was not because of himself. He decided to go to a program that he felt would better highlight his skills, and I don't blame him one bit.
This all circles back to the Jim issue. Jim is a stubborn dude. Always has been and always will be. He is always right, just ask him. He's snarky and refuses to admit when he's wrong. Nobody can dispute that. If you dispute that, you're just lying to yourself. Jim isn't for everyone (players/fans/announcers etc.) and it's cost him some very talented players this year.