Going back 20 years, there are probably 4 HOF quarterbacks.
Brady, Peyton, Rodgers, and Brees.
(Favre, too. Though I'd consider him more of a 90s QB)
That's it. But I'm more conservative when it comes to HOF than most.
If you want to argue for Roethlisberger, fine. But the guy won 2 super bowls early in his career and did nothing for the last decade of it. He wasn't ever a transcendent QB. But fine. It's not a hill I'm willing to die on.
Matt Stafford has a career 86-95-1 record. He's won a championship, sure. But he doesn't stand out in a way that the HOF needs to include him to tell story of the NFL during the past decade. Nothing is lost if he isn't memorialized.