Must they be "retro" styled to carry the old name? Look at the Camaro. The last generation looked nothing like the new one or the old ones. Not much was said about it not being a real camaro. Same goes for the mustang. The generation before the current s197 (ie, "new edge") looks nothing at all like the first generation cars. But people never complained that it wasn't a real mustang.

Cars change and evolve over time. I guess it's a gray area.