I think most teams with stud QBs will stick with late round QB choices until they HAVE to make a move. They will hold the hope they are developing the next Tom Brady from their 6th round choice.
Since QBs can play into their 40s these days with all the rules protecting them, I don't think there is a sense of urgency yet for Manning or Brady. Plus, you don't want to put your organization through what the Packers and Eagles have recently gone through. It is really hard and a lot of people's jobs are resting on that one guy's ability to produce.
Not to mention, the list of guys succeeding like Rodgers has is about 2 names long - Steve Young and Aaron Rodgers. Most guys that follow a big time QB are going to suffer from playing in his shadow.
In my NFL team that I'm going to buy some day (looking for Cafe partners to pitch into my buying group
) would handle this situation by trading for a QB when it became necessary. Someone that could manage the team and get by while we transition into finding a franchise QB. I think an organization is far better suited to handle a few bad years at QB after their stud retires rather than going through highly drafted QBs that bust or hitting on a good QB and having to dispense of your HoFer.
I'm sure there is more than one "right" way to do it, but that would be my philosophy.