Well firstly, the label 'fools gold' is a label reserved more for a player who you think will be your next MVP and in reality, isn't even VIP. I don't think anyone is predicting Lock is going to be the next Montana. He's a raw and untapped talent. To say he's done and over is just as foolish as to say he's destined to set every franchise record at the position. He's proven nothing, and been given few tools to do so.
Success at QB, and really many high demand, high pressure leadership positions is as much a function of timing and circumstance as it is talent and skill. Take a guy with an average arm , average game, but the ability to learn and pair him with a great teacher and you can win a championship with him.
On the flip, take a guy with arm talent, athleticism, and the same ability to learn and put him under subpar coaching and in an uninspired scheme, and you get .500 at best.
And if you want to get into sports psychology, it's often those players who are most passionate (emotion-based driver rooted in sensitivity), and who's skill is most tied to the dynamics of interpersonal relationships (particularly between that of teacher and student) that achieve the highest success because of a deep well of emotional reserve (strength of will) but are also susceptible to the wheels coming off if the situation isn't right. Feed the well for folks like them and their ceiling gets higher and higher. Don't feed it in their early careers where insecurity and unsuredness can dominate, and the wheels can slowly come off. Lock, to me, smells like this kind of guy. Give him some support, guve him good coaching, let him grow, and his potential is elevated.
Truth is we have no idea what Lock can do. The real truth to who and what he is, is yet to be written. But of all the guys you could give a shot to, he's as good as any. If you take the word of his #1 receiver in Denver as any indication, Lock is a guy who defines untapped potential, is imminently coachable and was just in the wrong spot, with the wrong staff. He should know better than anyone on this board.