I can't help but think a lot of how well most quarterbacks do or don't develop has to do with coaching. I sometimes wonder whether it's as much as 75% of their performance. Certainly somebody like Peyton Manning would've been who he was almost regardless of where he played. But even in the case of Brady, I feel like having a coaching staff who early on helped him slow the game down some was huge -- and gave him the cushion he needed to work on things like his deep ball as he got further into his career. So for that reason alone, if you're choosing Joneses, I think part of the reason you'd be more bullish on Mac than Daniel has to be Belichick/McDaniels vs. Pat Shurmer/Mike Shula and Joe Judge/Jason Garrett.
This isn't to say that Bill is some magician who would've had, say, Jarrett Stidham playing like this in his rookie season -- personally, I think he still places a much higher priority on decision making over tools at the QB position than most coaches. And certainly, Daniel Jones has shown flashes of tools. But the coaching/development piece is just a huge reason I don't think Mac turns out anything like Daniel -- if for no reason than I just don't ever imagine Bill pushing Mac to sling it the way the NYG have with Daniel from time to time, often with disastrous results.