great thread.
i follow (and hold) asbury, where real world services are far above just fixed cost offset. they have tried to build services to sustain breakeven in a typical recession scenario. and they have a nice ratio of reliable japanese\korean models to luxury brands.

asbury seem to run on a 'local oligopoly' hypothesis, which is to cluster high quality dealerships within a certain geo-logistical distance. this allows them to exceed some car selection\variety threshold while keeping low transport costs, and share staff in a pinch.
i dont know how valid this model is, but one can see a pattern in their dealers acquired\disposed.
of course, this would not work w/out great capital allocation in a rough business; especially as trump brutalizes the entire auto ecosystem.