I've tested in my own model 3 and the range and kwh usage is actually pretty accurate as advertised assuming you accelerate slowly, drive the speed limit, and don't run the heat, and don't have a strong headwind. Many people, including myself, absolutely do not drive like that, so the range will be less.
This is honestly true for the ICE estimates as well. It’s just that people have a lot more range anxiety when they can’t find a refueling spot every other street corner.
Not that I’m condoning it. And not that they’ve always gotten away with it. They need to be held accountable to come up with reasonable range expectations.
But also ICE are so inefficient that a small percentage change doesn't affect them so much because you're wasting 80% of the energy anyway so you load up megawatts hour of power when you refuel. On BEVs losing 4kw of power for heating or other stuff means a lot because you waste only around 5% of the energy, so adding 1 or 2 or 3% of other losses will impact the small energy storage you have.
It seems like it's an issue with manufacturing consistency/quality. The report said some cars were getting literally half their advertised range on daily commutes. That's not an amount that could be accounted for by driving styles.
Yeah it's all about ideal conditions, and same for ICE as the other reply said. Even external temperature matters for EVs too, if it's too cold the battery won't perform as well.
Running the heat can be energy draining because you don't have a hot engine to draw air from. Using the heated seats is much more efficient but of course less comfortable in cold weather.