He get's that narrative because he wins. However, just like with any QB.....if his career progresses and he never gets to a Super Bowl.....that narrative will change.
https://www.espn.com/nfl/stats/team/_/view/defense/table/passing/sort/totalPointsPerGame/dir/asc
Why do the Bills win. Bills 2nd in PPG defense (even with tons of secondary injuries) might help that.
I think even Goff could win with 2nd PPG defense every year