Its impossible to know for sure. Agree. Just as its impossible to know if he had held it back even further that he would have won.
That he wasnt gaining on the leaders in the final furlong, suggests that the pace slackened and having been ridden to win a race run in a strong gallop, the pacemakers werent good enough to ensure it. Those ridden closer to the pace werent coming back. It is incorrect to say that he was ridden for speed, he was ridden to come late using his stamina.
That and the form of the arc, last years King George and all form on right handed tracks suggests that he ran his race. Yes, the ride may have cost him some distance, but it is a big stretch to think that it cost him the race.
As I said, angles are good to have, and those who think that he is the moral winner of the race (best horse) make the market for those who underestimate the winner and runner up.