Perhaps the BEST B1G Forum anywhere, here at College Football Fan Site, CFB51!!!

No one with his tools would have a plan B, and that's what makes it lazy to say he should have.

Here, in Bill James' big historical abstract book, he posits that baseball players like Kirby Puckett probably have to be better than average to even get to the big leagues and that MLB players with that body type are probably all above-average because scouts would always argue against them.  They had to overcome that to eventually "make it."

I sort of see the same thing with all-time great QBs - Montana didn't have a special arm or running ability, Brady didn't, Manning didn't, and Brees didn't (esp post-shoulder injury). 
Favre did, Marino did, and some others, but they're not considered to be the best in hushed tones over an open fire. 
The magical ones are - the ones with guile and happenstance and sheer will....you know, the silliness people come up with when discussing NFL QBs. 

Those guys who just had a "good enough" arm HAD to do more in order to be good or great.  If Peyton Manning's dad was a truck driver, he'd have been a decent college QB that most of us kind of remember.  He HAD to be a deep-dive football nerd son-of-a-player who could call his own game in order to "make it." 
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But alas, this is why I usually steer clear of NFL stuff, because the backwards horseshit way QBs are considered drives me insane.  As if 80% of their careers isn't determined by sheer luck.

I notice you leave Brees off your list of Peyton/Brady. Brees had all the pocket scientist, field general qualities and threw with elite level accuracy. He had sneaky good running ability, though. He would never be described as a "running QB", but he was elusive in the pocket and very smart about when to scramble for yards. It was just one more thing defenses needed to worry about, and one more thing was enough.