And with a plugin model Prius... you won't use the ICE power unit at all on a typical commute (25 mile battery range on the current models).

Electric motors are 100% efficient

Umm what? Have you never heard of the laws of thermodynamics? I mean, the overall thrust of your argument is correct, but that statement is just nonsense.

Oh, and using regenerative brakes will always waste more energy than not using brakes at all and simply moving at a constant speed. Regenerative brakes are only efficient compared to conventional brakes, which waste all of their energy as heat. Braking more in the city driving doesn't improve an EV's efficiency there compared to using that same EV on a highway (aside from the fact that you're driving more slowly overall,) it just improves its relative efficiency compared to ICE vehicles with conventional brakes.

Gasoline powered engines are very inefficient in terms of getting all of the potential energy out of it's fuel source. They do have a sweet spot, usually somewhere between 2,000 and 3,500 rpm and most companies will tune their vehicles to be at highway speeds while in that sweet spot. The rpm range from idle (ICEs needing to idle at stoplights decrease city MPG) up to that sweet spot is less fuel efficient than rolling around in the sweet spot, so a lot of stop and go driving will see a gas motor running out of it's fuel efficient range quit a bit.

Electric motors have the same efficiency at any rpm and they don't use energy while the car is sitting still.

I saw those after I posted, and I’m a bit surprised. I always thought the reason EVs lose range on highways was closely related to the reason they don’t have gears. I guess I’ll have to revisit it.