with less and less contact and actual game type conditions in practice, i think the pocket guys have a definite inherent advantage over the dual threat guys as far as roster position.
like Mike said, "everybody has a plan, till you get hit in the face".
but absent real game conditions in practice sometimes, or as close to them as possible without being reckless, the flaws in the plan don't get exposed until you're being punched in the face by another team, with little chance to re think anything at that point.
and some guys are just better practice performers, and others seem to shine only once the lights go on.
with no spring games or open scrimmages anymore, and no touching the QB in practice, it's like picking the best golfer just off their driving range performance, or best basketball player, without ever going hard 5 on 5..
and with coaches at non elite schools feeling like their season, or careers, are on the line with every snap and every game, said coaches are very reticent to make a QB change once a starter has been crowned, even if crowned so in non live game conditions, other than when forced to by injury or sustained lack of production..