Payton couldn’t convince Jimmy Graham to stay back in 2015. Trades or big name departures are rarely a reflection of the HC’s lack of respect. Player availability and salary cap are big factors especially in Lattimore’s case.
IMO they traded JG because he didn't show up in most of the big games, was demanding unrealistic contract terms and many believe (and my son called it at the time) the fumble near the goal line against Atlanta with the playoffs still in the balance was the final straw......I really don't think CSP tried to convince him to stay unless there is some evidence I'm unaware of.....
The rest of your post I mostly don't disagree with....