The Tesla "can" get 3.3 miles per kWh if driven very nicely. Most of the tests completed by magazines and such are done in a manufacturer friendly manner. They have to stay on their good side to continue to get vehicles for free to test. So, while they may be real tests, they are done in the most favorable manner possible. If you drive a Tesla, constant speed of 55 MPH with no elevation changes in 75 degree weather, you'll even outperform the EPA range. But, when I talk about normal driving, that means keeping up with the flow of traffic, elevation changes. Not always the best weather conditions, etc, etc. When I travel across the wide open California or Arizona deserts, I can assure you, I'm not travelling at 55 or 65 MPH. Speed limits are in the 70-75 MPH range. Get to Texas and they get up to 80 or 85 MPH. Consider that "most" drivers drive 5-15 MPH over the speed limit and I'm talking about Driving a Tesla at 75-80 MPH. I've had both, the Model 3 and Model S. Both of them averaged around 350-360 wh/mi. Using the low end figure, calculates out to about 2.85 miles per wh. If you push closer to the 80-85 mph range. You quickly get down closer to 2.5 miles per wh.
My current Model S is rated at 365 miles. If I go to Arizona in January, in the evening when it gets down into the 30's or 40's, I'm lucky if I get 200 miles in range at about 80-85 mph, which is keeping up the flow of traffic on the wide open desert freeways.
While Tesla has managed to increase the range ratings from around 300 to 400, despite still having the same 100 kWh battery, I've barely noticed any change in the more important wh/mi figure from my prior 300 mile rated car to my current 365 mile rated car. Can't speak to the new ones rated at over 400 miles. Point is, my 300 mile car used about 350-360 wh per mile. My current 360 mile rated car also uses about 350-360 wh per mile. Same size battery between the two cars, thus, roughly the same "real world" range.