He wasn't that good of a QB. If he had the talent he thinks he has then he would be signed. No talent, a big mouth and not being a team player means he doesn't play. He could shut up, practice more and take care of the team but that isn't how he rolls.
Are you saying he gave up a promising career in football because he didn't play football very well?
He didn't have a promising career. He had already been cut several times and then began taking a knee to bring attention to himself. Are you trying to say he is in the same league and a Brady/Elway/Manning etc...? He simply isn't that good. If he was, nobody would care what he believes as long as he produced wins, and he didn't.