Did it ever occur to you that maybe someone had looked into this before? Actually, lots of someones with PHDs have and find the opposite of you. Not only that companies are staking $10Bs on developing EVs, do you think they haven't looked at this either? Does that make you curious enough to read what they have written and see if perhaps your napkin model might not be accurate or are you content to be secure in your conclusion?
Here's a few if you are interested
https://www.carbonbrief.org/factcheck-how-electric-vehicles-...
https://www.transportenvironment.org/sites/te/files/download...