20 teams (with Good to Great QBs) know that they have no chance at the playoffs without good QB and they will never trade their starting QB.
In Today's NFL there is not a single team with two Good/Great starters. Even NE has an unproven 2nd year QB behind Brady.
THe only chance would be trade for other teams garbage QB. You can pick your poison from that list
Cleveland - Manziel
Oakland - David Carr
Buffalo - EJ Manuel
Titans - ???
Houston Ryan Fitzpatrick
Jacksonville - Bortles (You have to give him time)
Tampa Bay -
Minnesota - Bridgewater (He showed flashes)
NY Jets - Geno Smith
You are not going to get Rodgers, Brady, Manning(s), BigBen, Mat Ryan, Rivers, Brees, etc.