i agree with your last paragraph. NFL qbs are coming from one read, RPO, simplistic offenses into complicated NFL offenses and asked to play right away.Has anything actually changed that much? Look at this list and count the busts:
http://www.drafthistory.com/index.php/positions/qb
I think it's just more obvious now, because these guys are coming from more aerial offenses in high school/college and being asked to do it sooner, whereas before they were sitting for a bit and would eventually either just never start or be given a chance to start and kind of fade into irrelevance. But it seems like the bust rate has always been high.
NFL Coaches would def have their rookie qb on the bench for a year but fans (and ownership) are forcing them to win NOW or we'll replace you so they are pressured to play their first rd "franchise QB" before they are ready and it's just a domino effect.. its a recipe for disaster.