If the Bears do move on from Cutler in a couple years, and Shanahan is the head coach. He will have failed and he will probably not be the guy to make the next selection. Presumably, an entrenched GM would then get the chance to start fresh at that time. You avoid throwing away the future by not trading anymore future draft picks, whether that is for current veterans or even moving up in the draft. They can hire a GM and Shanahan, try and win the next couple years without levering the future and while still turning over the roster with younger players. I'm not necessarily saying he has to be the guy, but there is nobody currently out there who is a better bet to win the next few years and no obvious better choices. There's a bunch of lottery tickets out there with the same resumes as a million previous failed head coaches.