We're just talking about my personal opinion, and I realize that I'm going against the popular grain but I'd have a hard time putting any kind of number on it just due to the fact that we honestly have no idea about Belichick's plans.
You're basing your analysis primarily on a poor preseason performance, which may not mean a damn thing in the eyes of Bill Belichick. One would think that he pretty much already assumed that he sucks ass as a pure pocket passer, especially in our system--so your conclusion that he'll definitely be cut based on 2 poor performances so far would then mean that you think Belichick somehow expected more.
While that's certainly reasonable and anything is possible, I personally am not as certain about it as you seem to be. If you absolutely held a gun to my head I'd still say that there's a 50/50 chance. We simply don't know whether or not Belichick feels that it's possible that he can utilize his strengths on any level throughout the season, or possibly even next season when the situation is revisited. In the meantime it's certainly possible that a full season of tutelage under Brady, McDaniels and Belichick, along with scout team QB reps (vs read option teams), the proper film study etc may lead to some improvements in his mechanics.
I think in a nutshell I'm trying to say that the plan all along may have been to bring him in slowly and allow him to try and turn things around, and it would seem awfully strange to think that he'd then automatically cut him.
I think I tried to show some reasoning in the above comments. Understand that I'm not claiming to be "right," I'm just giving another side of things and explaining why I personally am not convinced that this is as simple as a preseason game or two. There's still some thinking that there may be a bigger picture in play here.
