It wouldn’t be the first time they got something wrong.
Clearly this is a marketing gimmick, and are the same individuals as those represented in the Pitt Greats mascot races during games. And for marketing, you would want to pick the most generally well-known and culturally pervasive individuals. With the criteria being the most famous Pitt football alumni to the general population, I think one would be hard pressed to argue others at this point.
So who you pick depends how you define a Mt. Rushmore: is it the best players, the most famous, the individuals with the greatest impact on the program? I tend to favor those having the greatest historic impact.
I think, given only one mountain ala the real Mt. Rushmore, and selecting individuals that had the most profound impact on Pitt football, I'd pick Jock Sutherland and Tony Dorsett to start. IMO, are the two that are easiest to pick.
Sutherland was a consensus All-American guard and played on two of Pop Warner's national championship teams ('15 & '16) as well as the undefeated 1917 team. Replacing Warner, he became Pitt's all-time most successful coach with and an .818 winning percentage, seven Eastern championships, four Rose Bowl appearances, and five national titles over 15 seasons. As a student, he also lettered in track & field and wrestling and eventually served as a Pitt dental professor. A Pitt man through-and-through, he won championships while battling a university administration hell bent on deemphasis, even agreeing to stay on as coach under the imposition of crippling restrictions, until finally, they made things so untenable that they forced his resignation. Leaving him off Pitt Rushmore would be like leaving Knute Rockne off of Notre Dame's Rushmore. All conversations about individuals embodying Pitt football begin with Jock.
Dorsett, a four-time All-American and PItt's only Heisman winner who also smashed NCAA record books, was the local kid that decided to help bring Pitt back to the national dominance when going to Pitt was far from sexy; a domnance was sorely absent since Sutherland had been forced out (not including a smattering of good seasons in between). Without Dorsett, it is easy to imagine Majors not winning the 1976 title, and who knows how things may have been different. And Dorsett has remained a loyal Pitt man well after his playing days and Hall-of-Fame inductions, never missing an opportunity to lend his voice, name, or image to support the program. If one individual emodies the modern era of Pitt football, I think it is Dorsett.
After that, it gets difficult, if not impossible, to slot the last two as there are so many great players and coaches: Arthur Mosse, Joe Thompson, Pop Warner, Bob Peck, Marshall Goldberg, John Michelosoen, Mike Ditka, Hugh Green, Dan Marino, Bill Fralic, Larry Fitzgerald, Donald...you could make an argument for any of them, and others.