Apparently General Motors had to develop expertise in the used car market in order to support its dealers. When I worked in the business, that market was international, though confined to North America. Michigan cars were taken to Mexico and sold there, as they were generally in poor shape because of the salt used on the roads in winter. Used Cars from Texas and Florida were brought to Michigan, as they were in better condition and could be sold for more.
Once or twice a month, the used car team appeared at the dealership. They were gypsies of a sort, moving north and south, dealing for cars, and notifiying their carriers when and where to pick up their purchases and deliver their sales. I drove them on and off the trucks, a frightening task, though I don’t recall that I ever dropped a car off the rail. I think I came close on at least one occasion, though.
The used car team communicated with our dealership through a stream of telephone numbers, phone booths I suppose, that they left at the dealership like a trail of bread crumbs. Cell phones and the internet must have made that process much easier.