I’m not really in favor of naming anyone greatest of all time. Greatest of an era is better suited. And in most cases who you grew up with or first made impression is difficult to surpass.
My grandfather swore Sammy Baugh was greatest he ever saw, my dad Johnny Unitas. Did they think the next eras QB’s were great, yes but no one made the lasting impressions of those. Much like I was impressed as a kid in 60’s with Namath before Dandy, Roger and others caught my imagination.
I’d agree that Montana was greatest of his era and one of the all time greatest. And in a Cap era when we haven’t really had dynasties what Brady accomplished with Bill and Pats was truly great. And the fact he did it with Tampa too punctuates his greatness. You just can’t take away those 7 Rings. And Mahomes is on the verge of reaching immortality as well.
Problem with Dak regardless whatever personal stats he puts up will never be placed into those categories. Instead he’ll be in that next group of QB’s without winning Rings which isn’t all bad.
And why drawing these type of comparisons the OP is attempting is more about the frustration from the criticisms. But that’s the nature of the business. Ask Dandy, Morton, Danny and Romo.
That’s just Cowboys . There’s a long list of NFL QB’s that fall into this next group cause weren’t on teams with Rings. It is what it is. Winning leaves no doubt. The rest will always be argued. That’s the nature of the QB position. Fans always have their favs and will go to bat for them.