Besides the legal aspects (which prohibit sich cars from existing), such a car needs to be largely developed from scratch, as it obviously can't use any of the

Besides the legal aspects (which prohibit sich cars from existing), such a car needs to be largely developed from scratch, as it obviously can't use any of the existing E/E, so a new one has to de developed, this includes essentially a new platform development with the new E/E. I can only guess the development costs, but they will be somewhere in the billions. There is no way any car manufacturer is stupid enough for that.