Andrew Luck will definitely have the better career. Cam,RG3,and Vick will NEVER WIN A SUPERBOWL. Cam got exposed by the Giants. RG3 will be as well. Vick has been figured out the last 2 years and hadnt done sh*t for my team. These guys are simply running backs that throw the ball. They dont have the IQ to play inside the pocket well.
Cam and RGIII are more than just running backs that can throw with accuracy. With Vick you're right, because he's already old and still hasn't learned and was more of a runner when he first came into the league. They've shown more than Vick did when he first came into the league. Who knows if they will learn, they definitely could, but then again they might not, we'll see.
But all these dudes are better pocket passers than Vick. Vick plays hero ball way too much. RGIII does it more so than Cam right now, which isn't good given his size. Cam can take the beatings, he's built like Roethlisberger. Cam needs to work on his over the middle passing. He's more accurate outside the numbers, and thus tries to work out there too much, limiting the field the defense has to worry about. Defenses have keyed on this, and thus you have his sophomore slump. They need to get Cam a quick, sudden slot WR to work the middle. It'll work wonders for his game. Steve can do that, but he's so good outside too, it'd be best to have another quick fast twitch guy in the slot to wreak havoc. They need to quit with that option read stuff too, only use that when he's having a bad day passing or you need short yardage in crunch time. Same with RGIII.
Just look at Steve Young, dude was always trying to run around and play hero ball with Tampa Bay when he first came into the league. That never worked out. He went to SF and Bill Walsh revolutionized his game. These guys just need to be taught more, and learn on the field too. It's a process, but they either figure it out (like Young) or they don't. We'll see (although Young's career did end on concussions too, but he did enough before that to carve out a good career.)
Luck is just legit as fu*k, groomed to be a QB all his life. Son of a QB. He's way ahead of all these guys experience wise and has been taught more about how to operate out of the pocket. People always say you can't learn pocket presence but that's a lie. Eli Manning had very poor pocket presence even with all his teaching when he first got in the league. Some even called him a bust his rookie year. Lots of chuck and ducks. We know what happened there.