This is a flaw in inventory control (too much of it), and it can be fixed. The toyota production system is about getting the car to the customer as quickly as possible.
If you were smart you would organize your production/inventory into a Just In Time system. Every car is a bespoke order, each store has a demo of each type of vehicle available for test drives.
There's already an order of magnitude more used cars going around that fundamentally can't fit this model. Savvy individual buyers don't buy new anyway; setting up your new car distribution system based on efficiently serving a savvy customer in a way that doesn't extend to the rest of your business doesn't make much sense.
If you were smart you would organize your production/inventory into a Just In Time system. Every car is a bespoke order, each store has a demo of each type of vehicle available for test drives.