Sounds a lot like age discrimination. So you have different concerns re hiring someone of P's age vs. some younger age, just based on age only? I'm sure that thinking doesn't carry over into your hiring decisions at BL Inc. So how much better would P have to be to get you to hire him over some guy 45 years old? At what age would it not be a concern? Do you ask both "how long do you plan on coaching"? Would you have hired Paterno at 61; think he might have lasted longer than Weiss or Kragthorpe or Locklsey or Haywood? Is there a 66 age limit on Uconn head coaching? What is the average time in grade for BCS coaches or better the median, would bet not much over 5 years. Even if you don't take a snapshot and just go by how long a coach lasts at a school don't think it would be 7 or 8 years (let's see ND has Willingham 3 years, guy before him 4 years, Weiss 4 years; BCU has ...) . How many head coaches have been in BE for same team for 5 years. Probably can count on one finger. Lets see - under 5 years; BE a lot; ACC - BCU, Terps, NC, FSU, NCS, Miami, Virginia (lost interest in listing). For every Beamer there are quite a few Kellys and Dickrods so why not hire a coach to his "dream job", he might stay longer and do more good than the "appropriately aged candidate". The Terps are lucky, they hired a guy to his dream job and he was well under 61 years of age, I'm sure this new Terps coach will be coaching Terps well into the next decade.
And since the time it takes to learn if P was a good hire is "part of your concern for hiring someone of P's age" what are the other parts related to age? As you explain each concern, let me know at what age this concern would begin to reduce and at what age it would no longer be a concern.