McNair's TD-to-INT ratio and passer rating and completion percentages say otherwise, in general.
To put it in perspective, Dak's worst season was a season with a 22-13 TD-to-INT ratio and a passer rating in the high mid-80's. That's his floor so far. Pretty positive McNair didn't have a passing season as good as Dak's worst season until his 7th year in the league.
Dak's 62.9 completion percentage in his worst season last year? McNair only topped that twice in his career, and it wasn't until the very end when he was a savvy veteran in his mid-30's and wasn't a runner anymore. Everybody crying that Dak is inaccurate would have lynched McNair. Let's be honest.
And it wasn't until McNair was a wily 9th year, 30-year old veteran that his passing game improved to the point where he posted, for the only time in his career, a great TD-to-INT ratio and a passer rating that hit 100. Things Prescott already did as a rookie (and did them even better than McNair, by a good margin).