You are right, but now we are not discussing thermal efficiency, but total mpg which is related, but not the same thing. Efficiency being equal, you'll get more

You are right, but now we are not discussing thermal efficiency, but total mpg which is related, but not the same thing. Efficiency being equal, you'll get more mileage from an electric car, because it can get back some energy from regenerative breaking, and it definitely has less internal friction.