Actually, it's not just the luxury marques doing this. You won't see the name of the make on the backs of new Hondas, Toyotas, Hyundais, Chevys, and others. (not really counting Ford and Nissan since their logos are their names, but they also don't have their names separately).

Not really news, but an interesting footnote. They probably figure there is enough brand recognition to be able to do away with it, as well as drawing folks in who might have a particular (negative) presupposition about the brand.