I think JR can do it too (he has the physical skills) but he has to dedicate himself mentally. He needs to show us that he has that drive and will to want to win. He knows we don't have the best offensive line so he has to report to training camp in shape and ready to run and get out of the pocket. I think he may have gotten cocky since he came on strong at the end of last season. He was picked number one overall and paid like an overall number one pick. And with that comes the huge responsibility of getting us to the SuperBowl one day.
With that being said, I think he should be starting ahead of Fry not unless the Raiders have given up on him. Maybe he has gotten on Al's bad side and we know what happens when Al gets pissed at you.
So his demotion is pretty much his fault for not preparing and playing up to his potential.