Leaving everyone to go figure out efficiency obfuscates what should be a defining characteristics of these offerings!
I would have figured that rolling resistance and air resistance account for the huge majority of the energy usage without much room for improvement over eg a Model 3, unless you make it look like an F1 car or give it solid tires or something.
But it's something I feel like should be at forefront of mind. Competitors should be trying to get to top of pack, but very few are >120 MPGe.
Also it should be more obvious that big E-SUVs, even if they have big range, are actually joule hogs. Seeing a 70 MPGe should be a turn off.
And if we do change architectures? The Aptera has been talking about a 337 MPGe system for a while. It's an incredibly impressive idea, but only if people have the context to understand relative efficiency versus other EVs. We need to be building the base knowledge to evaluate, to appreciate wins, and to keep car makers from regressing.
When I think of "MPGe", my incorrect intuition is that it's factoring in the cost of gas and the cost of electricity to create a cost per mile that results in an "MPGe" relative to gas prices. ie, a 60 MPGe car would cost half as much per mile as a 30 MPGe car.
But as mentioned, this is incorrect. "MPGe" is based purely on some idea of how much energy a gallon of gas has in kWh, and miles/kWh is used to calculate that.
The result is that a 60 MPGe car could cost just as much, if not more, to drive than a 30 MPG ICE if gas prices are low while electricity costs are high.
Miles per dollar would be extremely region specific. And temporally specific; it'd change as prices wax and wane. I don't see how such a MP$e would in practice work.
My understanding is much of the world does kWh/100KM, which by virtue of the constant gives a reasonable straight number. Tesla for example has a page called European Union Energy Label, where we get figures like: Model 3 Rear-Wheel Drive, 13,2 kWh/100 km. It's perceived as more human friendly I guess than .132kWh/KM.
It definitely does seem like having the two units - either 1 gallon or 33.7kWh EPA - makes it really hard for consumers to understand the relative merits of their vehicles.
This is even less of a concern with electric vehicles, both because any electric vehicle is already more environmentally friendly (you can feasibly charge with 100% renewable energy regardless of MPGe), and because the energy cost will always be lower than it was for gasoline vehicles, which leaves even less monetary value on the table for possible gains from efficiency improvements.
So almost nobody is going to care about that unless we end up in a world where electricity prices are dramatically higher than they are now.