Its not how many cars, its how much profit per vehicle versus the cost of overhead of these 'mega' car dealerships. With squeezed margins (e.g. 'employee pricing', Factory 0% Financing, etc.) the dealerships simply don't have the profit to continue operations. Most of them are based on a sales model that's decades old, and that is no longer valid.
You'll see the small, single line dealerships with old buildings in bad locations survive because their overhead is low (likely the buildings and equipment are paid for already).
Your favorite motorcycle shops are next...
