I'd think another value would be how handy someone is to wrench on their own car so that they drive the car as much as they are willing to complete their own repairs can allow more miles to be put on the speedo. Fewer miles if you let someone else do the wrenching. Therefore, learn to wrench and enjoy the miles.
Not all old guys stay home...I might just skew the mean for the 70 plus segment. In April and May I took my 77 year old self in my1965 Lotus Elan ( A car Sam Smith asserts is made of "Kleenex and Unicorn farts") 11,544 miles from my home in Colorado to the four furthest compass points in the Continental USA, Card Sound Road, FL, Madawaska ME, Jalama Beach CA and Cape Flattery WA. I also hit the highest town, (Alma, CO) the lowest, (Furnace Creek, CA) and the geographic centers of the 48 states (Lebanon KS) and the 50 states (Belle Fourche, SD) averaging 350 miles per day and 30 MPG. I have taken my old Lotus cars on an average of two trips per year of a thousand miles or so for the past 20 years and plan to do so for the next twenty, God willing!