I think that’s it mostly.
Certainly not because they’re problematic. I never implied that. I think the pre DEF engines are less problematic.
Another factor is people with enough money to pay cash buy newer if not new.
Many people would rather pay interest through the nose because they dont actually have much cash and want new.
Another reason as I looked at used is many of them have not been garaged kept and look really used: worn upholstery, carpet, seats.