It's actually a "hot dog & soda" combo, and has been since its introduction in 1984. My understanding is that Costco has cheapened their hot dogs in a few ways

It's actually a "hot dog & soda" combo, and has been since its introduction in 1984. My understanding is that Costco has cheapened their hot dogs in a few ways, and has owned their own (cost-optimized) hot dog factories for over a decade. And is seriously ruthless about "whoever is cheaper" on their soda supplier. And obviously the combo is a textbook loss leader.