The success of Carmax has long been that they are just better on the buy side than anyone else. They are just a large used car dealer with excellent auction buying strategy. It makes sense to buy from Carmax but it doesn't make a ton of sense to sell there. You know they are trying to squeeze you on that side of the deal.

Carmax never loses money. Carvana has never earned a profit. It's sort of a big difference!