I consider things a little differently.
Most of us expect the season to be somewhere near .500. Maybe 2 or 3 games over, and everyone is happy, post Ben. 11-6 would be awesome given OL, no clear starting QB, ILB issues, etc.
If that is the case, and we will be looking up at Buffalo, KC and perhaps even the Bungles, then there is little point in keeping 3 "sorta starting" QBs.
Obviously Pickett is the future, either later in this season, or next year.
But if Trubisky starts and gets hurt, Pickett gets the ball. If he gets hurt too, who really cares about the rest of the season? I mean we are looking at fixing the holes in next year's draft.....so why do we need a QB3 that might bring a return --- for next year's draft --- if dealt to a team in need now? In that scenario, I would rather be 5-11 with QB3Project and better picks for next year than to have a serviceable QB3 like Rudy and finish 9-8 drafting at 20 again.
If one of the two QBs at 1 and 2 make it thru the season, then we should have traded Rudy to a team with need.