You're not factoring that into your math at all.. and that's a pretty big miss.
The shorter term/unlimited miles does favor someone who drives more than 15K miles/year.. but it's not so huge a difference as the old program knowing that those driving less were likely either going to hit that 100K mile not too far past 5 years anyways.. or would have to buy newer/lower mile (read: much more expensive) CPO vehicles in the first place.
I am actually astounded that for pretty much short money I can extend the CPO to 10 year/unlimited.. with excellent coverage.. on a motor that's pretty complex (super and turbo charged, high compression, etc.) and also it's an active AWD system... but also, a car that relies on electronics a ton, especially the Sensus.
It's the #1 factor I'm going to buy a Volvo this time instead of a BMW (current) or Audi (past). Thank goodness the car is also pretty great.. just wish they had an option for a 6 cylinder with some more nuts (I don't like the complexity of the T8 and many reviews says the system impacts driveability).