John Delorean got certain pre-existing dealerships to go into contracts with him. I believe if you paid a dealership fee to Delorean you were garanteed a certain quantity of Deloreans the first year. There was a long costumer waiting list, and a lot of hype right before the car came out.
Some dealerships had to back out of the deal because they were urged by the big 3 automakers not to sell Deloreans at dealerships that mostly sold GM etc.
I can't remember the exact history how it went, but thats what I remember reading somewhere.