All three companies have several brands (VW has Porsche, Audi, Skoda etc.) and each of their brands have several models. They are also produced in several factories in different countries.
4-5-6 years ago, when Tesla demonstrated to the world that an EV can have longish range and look attractive, the traditional car companies could have allocated resources and production lines to develop and produce competitive EVs. They would have been in a much better place to compete than tiny Tesla 5 years ago. But now, they are late in the game.
It's more a symptom of failed management than some function of a business law.