To play devil’s advocate, used car prices do not follow supply and demand. They follow perceived supply and demand by a conflict of interest. If you try to buy a used car, your salesman gives you info to push you to pay more. They have other lots to make it seem like there’s low supply.
Carvana and CarMax operate similarly.
And if you feel like knowledge is power, Manheim/Cox numbers don’t matter when you’re purchasing through a greedy middleman.