I think this is the main reason Goff was taken over him. I also think this is the reason he hasn't had success later in his NFL career.
He is definitely driven and has the physical gifts, but it has been noted that he lacks accountability, isn't liked in the locker room, and is generally "uncoachable."
I never liked the dude, but I am excited to see him on the field. Hopefully his lack of success over the last few years was humbling enough for him to adopt a new attitude If so, he may still see success.