Read what you wrote again. You say Carr was not better "over the course of the season"...except he was better over the course of the season (far better in fact) because those last six games count. The course of a season is the entire season. Dalton threw 4 TDs over his last six games. Carr threw 16. One got worse and the other got better.
Winston and Dalton had their chances, if not with fully with us, then with other teams. Winston had a chance to seize the moment last year and didn't, including with a 17-0 lead against Green Bay, a pretty perfect situation to come in and get a win. He didn't do it. He's gone. Time to let it go.