That’s on the regulators to define a metric, lest EVs compete on made up numbers. EVs are so new of course that organizations are still figuring this out globally.
No gasoline car uses the EPA fuel economy to do it's range estimation, EVEN WHEN IT WOULD BE BETTER FOR THEM TO DO SO, because it's wrong enough often enough to make a range estimation using it lose significant value.
Tesla has made a choice to stray from normal industry practice. If they have done so in an attempt to sway customers with the incorrect numbers, that should be considered fraud. That's pretty damn difficult to prove as a crime, but not hard to make likely in a civil case.
Do you have more convincing evidence of this because I have used many Toyota vehicles and they do not use EPA figures to do their range estimation, and can be conclusively shown to be using their internally measured "average mpg" figures to estimate range.
I'm mostly commenting on all manufacturers being conservative with fuel/energy use/metering. Even older vehicles I've had (carbureted pickup truck) usually have a gallon to so left in the tank on empty.