The upper limit is set at 70 which is the oldest coaches ages thus causing the age disparity between 42 and 70 to look greater than it really is. Just saying.....
The age disparity between 69 and 42 looks great because it is.
When Mullen was born Spurrier had already:
Graduated college
Won the Heisman trophy
Played 5 years of pro ball for the 49ers
About the time Mullen graduated high school Spurrier had already:
Been named ACC a Coach of the Year twice
Been named SEC Coach of the Year once
Was on his 6th coaching position