Because they want to appeal to that "broad market base." Apparently they haven't noticed that a lot of Americans want a car in an ad that screams, "this car will kick all those other cars' asses." Although.....I have to admit, when one of the GT40 guys said, "our car will put your Viper somewhere between earthworm and garden snake," THAT was cool.
They need to "muscle up" the Mustang ads, though.
It's kind of funny from a manufacturing/marketing standpoint. They want to raise the CAFE (Corporate Average Fuel Economy), yet they're pushing ads for the most gas-eating vehicles they make. You'd think they'd push for the Mustang, Focus, and Taurus. That T-bird ad with the Lamborghini (or whatever) is the best one to date, IMHO.