The year of no doubt obsessing over film study, the playbook, and practice reps certainly was an advantage for Brady in 2001. Although, I think the difference in eras is a more significant variable that presents a disadvantage for 2001-Brady when making comparisons to current quarterbacks. Otherwise I agree Jones has proven capable of being a competent NFL quarterback in his rookie season. The obvious question now is what's his ceiling? His (lack of) arm strength is the biggest concern in my opinion. I just don't see the velocity generally needed for consistent accuracy into tight windows.
You think Belichick would be considered the GOAT HC without having had Brady for 18 seasons? I suppose if you're trying to be entirely objective then you would conclude it goes both ways and each helped out the other equally. But I'm not interested in striving for objectivity in such debates so I'm coming down on Brady's side. BB just doesn't have nearly the success as a HC without Brady; the numbers and percentages are boldly there for anyone to see. On the other hand, Brady's 28-9 (4-0 in the postseason), a SB champion, a SB MVP, and a strong league MVP candidate without Belichick. Brady also has literally secured Arians entrance into the NFL HOF. Wannstedt could have only dreamed to be that lucky.