Even though Manning failed (miserably) at times last year, there weren't many QBs who have the experience and are able to make pre-snap adjustments plus read a defense like Peyton Manning can. To take it one step further, he had led DEN to 12+ win seasons on all three of his years there. That's pretty significant, as much as we like to make fun of his postseason woes. I think any GM will gladly take a #1 or #2 seed in the postseason, and go from there.
I think it all comes down to how much one believes his injury held him back, and whether or not they can make the necessary adjustments to try and limit his weaknesses (lame duck downfield throws), while taking advantage of the obvious strengths that he still possesses. In my opinion, they got the best of both worlds by still keeping a good to very good franchise QB, while also shaving 4m dollars off of the 2015 salary cap. In your scenario, they are not only throwing in the towel for 2015, but they are also hoping/wishing on a future QB from college. I think Elway is smart enough to realize that you still play Manning while he's able to play. Just my opinion.
