"and significant tax revenue for local communities" is true whether or not the factory owns the dealer, as the local branch of a factory-owned dealer likewise pays property, income, and sales tax.
Car dealers take up more property than, say, Tesla showrooms. Figure that a Tesla showroom usually has a few cars on display in the nice, climate-controlled, showroom and a few cars parked in the lot for test drives. You aren't walking into a Tesla showroom and driving out in a brand new Tesla. Since your property tax relates to how much property you have, these showrooms pay less property tax.
I remember there was some local pain when GM closed down Pontiac and Saturn dealerships and, suddenly, some nice property taxes stopped coming in from those dealerships.