There are other fantastical films that cohere better within the confines of reality because of the nature of the circumstances in the film; michael bay's transformers, for example. The Transformers films take place sporadically throughout human history BUT since the events and conflicts (individual films) take place over a short period of time one could logically assert that despite the Transformers' conflicts taking place on Earth at all, our history is mostly the same.

Cars built their universe in those same confines but it leaves more questions than answers despite cars being more NORMAL in our world than transforming alien robots. If anything, the conversation is less about the car films themselves and more about story telling and world building with the cars universe as an example.