JK,
I think many are having trouble getting by the 120 week quote, and for good reason. There has been very little explanation of the route to 120+ mile weeks. In your experience, how long does it take your runners to adapt to the increased mileage? Days, weeks, months, years? Is the mileage so relaxed that a person who previously ran high intensity 80-90 mile weeks can easily and immediately bump up? What is the occurence of injuries? Less or more than in people who previously ran more intense, but less mileage?
This sort of reminds me of talking about why Kenyans are so good by only looking at the short term training camps they attend. What about the years of aerobic devolopment running back and forth to school and such? That, among many other factors, of course, is what enables them to shoulder such a heavy training load later on, is it not?
There has been far too less time devoted to the process of attaining high mileage (progression/relaxed-easy running) than to the debate about whether or not the end result is necessary.