What's been ignored here are the great players without much around them. Elway at Stanford. Brees was mentioned. Marino split time in 2 of his 4 years at Pitt (unless it wan an injury issue, I'm not old enough to know). He had a great defense his whole career, but what else?
There are dozens of other great QBs with poor supporting casts.....yet if you look at the all-time career pass rating rankings, all of the P5 guys are from elite programs: Bama, OU, OSU, LSU, Oregon, Florida....before we get to Sam Howell of UNC.
.
Separately, I was mulling this over again, and we award the Heisman to the QB with the team having the best season. Most often, that includes a bunch of blowouts (that yes, the QB helped create), but that means a lot of stress-free football. I bet if you broke down each Heisman winner's season into "quarters in doubt" - where the outcome of the game was in doubt at the end of each quarter, many would score lower than 10. Meanwhile, there are QBs having great seasons on teams with no OL or running game or poor defenses going 7-5 and over half their quarters are in doubt (24+) that don't get a vote.
.
On another aside, just to show how much college football has changed, Ty Detmer had a career pass rating of 162.7 and Jalen Hurts' was 162.6. One was a Heisman winner and a legend and the other was replaced for a much better passer.