It has to do with this kind of draft grading system (this is from nfl.com, but most sites have similar - scroll down to the bottom of the page to see the grading system).    "Chance to become an NFL starter" is the 7th ranking, and the 4th or so of what is commonly seen.  So whereas Sam Darnold was graded 7.00, "Pro bowl caliber player" and QB Rosen and Mayfield were graded 6.19 and 6.02 respectively,  "should become instant starter", Josh Allen was given a grade for players more commo