0.9% exists to get people into cars (aka, volume) who otherwise might not come through the door + add origination fees + attract the type of people who are like

0.9% exists to get people into cars (aka, volume) who otherwise might not come through the door + add origination fees + attract the type of people who are likely to incur late payment fees. I would guess at a macro-level, the effective rate is much higher and more than offsets the 1.5% difference between safe treasuries. Lots of people buy based on "what would it take you to get into this car" monthly payments rather than TCO, so if you're a cash buyer and can safely arbitrage the interest rate difference, you're probably the exception. I suspect the local sales guy pockets any loan origination fees; the automaker is just paying that as commission for the actuarial likelihood that the people who finance will default at a rate that still makes it profitable when taking into account the benefits of maintaining low inventory in a given model year.