I'm still on the fence on this one. Here is what it comes down to.
Are there things that Quinn does currently during a game that Arch can't? I haven't seen something yet that I would say "yep, Arch wouldn't be able to do that".
Are there things that Arch can do currently during a game that Quinn can't? I think we have seen enough scrambles and deep balls to know that Arch is much better in just those two categories.
To me, you put the best talent on the field at every position so I keep asking "Are the coaches seeing something in practices that we aren't and that is telling them they have a better chance at winning with Quinn?"
As you referenced above, I'm sure there is a lot of Sark thinking that if he goes with Arch and fails, it will be thrown in his face that he should have just stuck with Quinn. So this may be the path of least resistance and he knows he will still have Arch and good talent next year.