How can you honestly "charge off" a debt as unlikely to be repaid, when you are quite likely to be repaid? It seems that in the case of a car loan you can usually reposses the collateral, which recently will have held value oreven appreciated in the interim.
Historically, car values underwent significant depreciation over time and loans that went delinquent were for vehicles that were "underwater"- their value was less than the loan. Its pretty much unprecedented for the value of a vehicle to actually increase at any point in time over its life, and how long this anomaly will go on for is very uncertain- another way to put it is that you don't change all of your process and accounting norms because of a temporary (at least as we think for now) supply issue.