They're not quite dead yet...

There still is a huge push to consolidate PBG stores
http://money.cnn.com/2008/01/19/news/companies/bc.gm.dealerships.ap/

Found this interesting
2006 New cars and light truck sales per dealer
Toyota: 1,821 *includes Scion
Chevrolet: 586

Lexus: 1,479
Cadillac: 154

I think the excess of dealerships only hurts GM.