If Joe Paterno had retired after his 70th birthday, PSU would've had a new coach for the 1997 season. Think about that. The first investigation into Sandusky happened in 1998. Think of all that could've been avoided by the program and the school if they had just parted ways with Joe at the very reasonable age of 70 years old.
From a strictly football standpoint, they would've won more games and certainly have a better record against OSU (and Michigan). With each passing year, as Joe got older and older, and elite players became less and less likely to commit because they didn't know how long Joe would last, the team got worse and worse. It got to the point where they were more interested in four win seasons than ten win seasons so long as those four wins were added to Joe's record and he could outlast Bobby Bowden for the all time wins record.
The McQueary incident in the locker room happened when the team wasn't good. If that had gone public, Joe would've been easily ousted (15 years too late). They covered it up, Joe lowered his standards and brought in some talent that won more games and criminally assaulted their fellow students. But all that is history.
Penn State underperformed for the last decade plus of the Paterno years and then through the sanctions. They have talent in their state and similar recruiting advantages to OSU. The PSU of the next 20 years is going to be a lot better than the PSU of the last 20 years since they finally got that albatross Paterno off their necks.