Also, electric cars cost more than diesel when recharging as Guy Martin demonstrated when he did Lejog with an electric vehicle. Cost of electricity: £204 compared to £140 on diesel .
If you are an utter plonker and only charge at superchargers on the motorway it will cost you more. For most people you will charge at home and find nicer places if you do need to supercharge. Do you fill up with Diesel on the motorway? I know I don't.
Further, he did his "test" in a converted ICE car and not in a properly designed EV. There is a reason that Tesla are best for long journeys, and cheaper, more efficient charging along with longer range is just part of that. They are designed to be electric.
Then of course, as time goes on Diesel is going to become more expensive as demand drops...