On a lot (really most) of 4WD/AWD drive vehicles, but especially those with 'full-time' (cries in Subaru), if you need to replace one tire 20k miles in (i.e. due to a road hazard etc) you then have to replace the entire set to avoid damaging the drivetrain.
I suppose in theory you could try to 'trust' shops to properly pro-rate such scenarios, however I'm skeptical that it could be implemented in a trustworthy way without being more trouble than it's worth.
Re-sell them to other vehicle operators that don’t need to worry about that to utilize the remaining life? Would be easier if we had more 3 wheelers but at least 2 tires can be sold as a set. And not extremely difficult to match sets of 3 odds together with another 3 odds if you have some infrastructure to get some network effects.
Cuz i’m sure the shop is doing that.
What kind of tire shops should I look for? Smaller ones or specialty ones?
Off-road driving.
additionally, most people have probably paid to replace tires worn due to imbalance or other issues. how would that be accounted for?