I think if he wanted to be on an NFL roster badly enough to take the backup QB money he was offered, he'd be on an NFL team.
I also think that if he is really as talented as he thinks he is and picked the right team to sign as a backup - Denver, for example - then he'd have gotten a shot to play, if not start, and would get offered starter money due to his performance.
I just don't think he's that good. Which is different than saying he didn't have a couple of good years.