Some go by NFL success as that creates their desired answer. To me, it's all about college success. For example: If one school produced nine Heisman Trophy-winning quarterbacks and All-American after All-American at quarterback that didn't win the Heisman Trophy for them but they didn't pan out in the NFL, that school wouldn't be Quarterback U?
Charlie Ward won the Heisman trophy at FSU playing quarterback yet never played in the NFL opting to play in the NBA instead. Does that diminish what he accomplished in college? Do the injuries that curtailed the careers of Dennis Onkotz and Ki-Jana Carter diminish what they accomplished in college?
If it's by what players accomplish in the NFL, what about the following players: Does what Terrelle Pryor accomplish count towards Ohio State's wide receivers? He never played WR at Ohio State but it's what he does in the NFL right? Does Antwan Randel-El count towards Indiana's receivers? He played quarterback at IU. Position changes are not uncommon. So why give credit to their alma mater for a position they never played at in college?
What about Matt Cassell? Does he count towards USC's quarterbacks? He never started a game and I believe attempted 30 passes in his college career. So what he accomplished in the NFL help USC as Quarterback U? Does Chris Hogan count towards Penn State's wide receivers?
Jack Lambert and James Harrison both went to Kent State. A hall-of-famer and near hall of famer, is Kent State more of a Linebacker U than Pitt?
To me, it's what you accomplish in college that should count towards a college being a position U.
I'll give you one further point of contention with me on a similar vein. Miami 2001. Some would call them the greatest college football team of all-time based primarily on what their players accomplished in the NFL. Why should anything a player accomplishes in the NFL influence what actually happened in the past. If the '01 Hurricanes produced 22 NFL hall of famers that doesn't change the fact they struggled to beat Boston College and only beat 14th ranked Virginia Tech by only two points on the field of play in 2001. Future accomplishments do not change past results and isn't that what should be compared. If anything, it shows how talented they were but not what they actually accomplished. If they were THAT great, they should have destroyed every opponent based on what their players accomplished in the NFL and they did not.
That's like proclaiming Bryce Harper's little league team the greatest ever because he played on it even though they may have not even made the LL World Series.
That was an extremely long answer for shoukd have been a much shorter one.