Both Goff and Prescott are elite quarterbacks. Stafford, Mahomes, Jackson, Allen, etc. are transcendent talents for different reasons.
At 35, Stafford is proving that he has the even more rare combination of physical skills and mental acuity that is required for sustained success in professional sport. These are the rarest of athletes, like Allyson Felix, Tom Brady, and LeBron James.
Consider Russell Wilson; he was great while he had his elite athleticism and mobility, but now that those skills have started to erode, he is struggling.
Time tells a lot.