People seem to always overlook the luck factor in sports in general, but it's really prevalent in football. It's a team game, but people want to act like one guy and his talent can make all the difference.
Roethlisberger is an ok QB. He won a SB while being fairly awful because he played for the Steelers with guys like Troy Polamalu on defense.
Brad Johnson won a SB with the Bucs and Trent fucking Dilfer did it with the Ravens because they got lucky and had All-World defenses.
Meanwhile, Cleveland has killed the careers of many a promising QB because that organization is a shit-show from top to bottom. If Mahomes goes to Cleveland in the draft he's a nobody who, if he was lucky, gets traded and works his way into a starting role somewhere else. More than likely he gets the shit pounded out of him and has the Cleveland stink put on him and carries a clipboard for the rest of his career or is out of the league within 5 years.
If Vince had gotten drafted literally anywhere else, I believe he'd still be in the NFL today. Instead, as luck would have it, he went to a mediocre to bad organization with the biggest loser shit stain for a HC who specifically hated Vince and didn't want him as his QB. 31-7 record as a starter. Improved his QB rating year after year. Got set up and blackballed. Out of the NFL. Imagine if Vince had gotten to play for a guy like Reid who wanted him, knew what he could do, and molded an offense around him. It would have been glorious.