Much less than 100% of electricity is... still more efficient than ICE? I don't see how that changes things.

US electricity averages 384g CO2/kWh, so EVs emit 100-130g/mile, equivalent to 90-110mpg. And that improves year on year, while an ICE is at best as efficient as when it was produced

while a very important aspect (and you're right that EV are more and more better on that), that isn't strictly thermodynamic efficiency you're talking about. For example, natural gas is a major fuel for electricity generation and, even at the same efficiency, it produces less CO2/KWh than say gasoline.