You're either just not remembering things well, or implementing some revisionist history.
All four of those players were dramatically better than what Nebraska has produced up front over the last 4+ seasons.
Sirles- started 41 games. Was All Big HM as a Junior and 2nd team All Big Ten as a Senior.
Gates - was on an All Big Ten team three times.
Sterup and Qvale endured some injuries that slowed their development. But came on strong as Seniors.
One thing of note about Nick Gates:
He started 25 games at Nebraska before his 21st birthday. Short of being one of the 4 to 5 elite high school recruiting teams each season, you can't win without an older and experienced offensive line in college football, especially in the Big Ten.