Any “greatest” discussion of course is just opinion but I think the linked CHFF article puts forth powerful support for Starr as the greatest QB ever.
Leadership is an elemental piece of quarterbacking – probably more important than gaudy passing stats. And that love his teammates had for their field general is an incredible sign of his leadership.
Starr was one of a very few that had the guts to stand up to Lombardi. He called the plays and was an extension of Lombardi on the field. He was a great field general.
He led the NFL in passer rating five times. Johnny Unitas led the league in passer rating just twice. Ditto Joe Montana. … And, lest we forget, Starr was the best postseason passer in NFL history, as evidenced by his record 104.8 playoff passer rating and 1.41 percent interception rate, also a postseason record (CHFF readers are well aware of the importance of not throwing picks in the playoffs). Starr played in an era when 80 was a decent passer rating. Yet he still performed more efficiently in the playoffs than folks such as Montana, Brady, Manning, Marino, Young and ... well, anybody, ever.
Comparing eras is difficult, but using stats like passer rating to compare players to their contemporaries first, and then to each other are IMO meaningful. Also, Starr’s career YPA is better than Marino’s and Montana’s, among others.
History also remembers Starr's Packers as a great running team, and that's certainly true of their earlier years. But the truth is that they typically passed the ball more effectively than they ran it, especially during their run of three straight, when they were a below-average running team.
Fans remember the early days of the Lombardi era and how they dominated teams with the power sweep, as well they should. But this article notes that for the three straight titles from 1965 through 1967, the Packers were 11th of 14 teams, 14th of 15 teams, and 4th of 16 teams in rushing. They were 2nd, 1st, and 1st in passing for those seasons.
When it comes to a combination of leadership, victories, big-game performances and statistical supremacy nobody – NOBODY – put together a more total package than Bart Starr, the greatest quarterback in NFL history.
As the article also says, Starr is the only QB with rings for the four fingers and thumb of his passing hand.