Good. When I was shopping for a used car a couple years ago, I found virtually no good candidates from private sellers because Carvana had completely gutted the second-hand car market where I live.
Their business model is to basically corner the market by buying _all_ the available newer used cars (often above book value) from private sellers and dealerships and then advertise the crap out of them on all the usual car listing websites with the goal of being the _only_ option that most people have for buying a used car.
I don't have a problem in principle with "no-haggle" dealers in general. Plenty of people don't mind paying more than they have to for a car, just to avoid talking to a stranger. But the way Carvana operates is just begging for some kind of regulation.