I'm ignoring nothing. If other successful coaches have those same issues, then your issue (Joker's attrition) is a crutch or an excuse. Stupes is operating with nothing less than other successful coaches have.
I'm not sure who the 3rd coach is--Auburn's??--but you never made the point because you either disregarded it or overlooked it. And if Pappaw had high attrition, why wasn't that commonly heard to help explain Joker's alleged lack of performance?
20th rated recruiting classes don't get you a national championship, or Texas would have won one this year. More to the story besides alleged attrition and recruiting class rankings. Those can be used as excuses to cover for poor coaching.
Unlike basketball, one great player in football doesn't make a huge difference. If that was the case, U of L would have challenged for a championship when Bridgewater and Parker were teaming up. There's more explaining the results you're citing than a good player or roster attrition.
Stupes hasn't been in the job long enough. The one common thing I do see is typical LPT in-game coaching.
LPT Football: Consistency sucks...
Most successful coaches don't inherit the roster mess Stoops did. But, that's obviously something you're not going to agree with. Good thing like most coaches he'll be given more than two years to prove his worth.
The three coaches are Brooks, Joker, and Stoops. And, being that two of the articles I used for my numbers on attrition were written during Joker's time at UK, I'd say it was used as a reason for Joker's lack of performance.
And, you are correct, top 20 classes don't lead to titles. This is also the case with Auburn. They had the top 20 classes, but they also had two top 10 classes in the four years leading up to their championship. As has every champion since 2002.
Bridgewater and Parker were a hell of a tandem, but even together they didn't have the impact of Newton. See his impact at the NFL level for the pathetic Panthers organization.
Finally, Stoops is going on his third year at UK. He's had significant attrition, really any attrition at all, his first season. Joker experienced that attrition on an annual basis during his three years. There seems to be some reason for that. If only I could put my finger on it...