Here's the extreme example I always reach for: Imagine BMW decides that it's cheaper for them to just make all 4 seat sedans instead of having some 2 seat models and some 4 seat models. They instead tell customers: "You're buying a 2-seater. You need to pay a $X/month 'sedan fee' to be allowed to sit in the rear seats." Would this be acceptable to many people? Of course not, and for the same reason that subscriptions for other things that are already part of your car should also be unacceptable.