[Mtntrek]

In my perception of tires over the decades it would seem that mfrs. balance rubber formulation to do certain things. Perhaps sell tires to differing markets.

Harder mixtures may indeed wear longer but might also give up traction and control.
Where a soft sticky compound might well grab very good but only last half the mileage.
Case in point: Would a NASCAR driver care if his tires lasted 40k? Or would 550 miles and a whole lot more G-force suffice?

I tend to prefer the highest rating in wet traction for tires, as water on the roads seems to be the biggest equalizer where I drive. YMMV.