Most dealers file the national players under competition for the sale. That is the wrong shelf. Between them they retail just under 3% of the used cars sold in this country, which is a rounding error against the franchise and independent base. On the buy side they take 13% of the used vehicles consumers sell, better than two million units a year.
Four times more in than out. So the balance goes back to wholesale, which is to say back to dealers.
They take the cleanest cars off the street, retail the best of them, and sell the rest back to you.
What that does to the lane
It changes what you are bidding on. If an outfit acquires two million consumer cars, retails a fraction, and wholesales the remainder, then a meaningful share of the pool in front of you at the sale has already been looked at and passed on by somebody with better data than the guy standing next to you.
That is not a pricing problem you can bid your way out of. You cannot outbid your way to a car that was never going to be in the lane, and paying up for the ones that are is how a unit gets bought wrong before it is ever priced.
Where it leaves a dealer
The cars did not disappear. They changed hands earlier, in a driveway, before anybody at your store had a chance to make a number. The supply question and the gross question are the same question, and both of them get answered upstream of the sale.
Which is the entire reason the buy side is where the work is now. Gross is decided when you buy the car.