You know, it used to be at the local tracks, the late model cars were just that, cars from the latest models of the manufacturers. When the design of the Camero began to win all the time, the late models began to take shape in that mold and today, a late model dirt car resembles no car on Earth. And, they all look alike but have different drive trains and that's what they are called.
NASCAR is no different in this respect and will follow the same line. Ten, fifteen years from now, people will be talking about how the Ford, or Chevy or Dodge or Nissan or Toyota or Honda is lord of the track. But most people won't be able to tell what make is what without the decals. Brand loyalty is great but those guys fielding cars will tell you that they want to win and if it's a certain manufacturer they use, they want it to be able to do the job. Remember, they are first and foremost, racers. Some have become car salesmen, but even there, some of those guys sell different cars than what they drive/own/work for. What drives these guys is the money. If they can't get it from one manufacturer, they'll go to another.