This won't be a long post. Part of Tesla's sales strategy is to claim that an M3 is cheaper to operate than an ICEr. In fact, when you configure a new Tesla you can select between a purchase price and a price discounted to reflect savings over a period of time. But is there real savings?
I just turned 14,000 miles on my October 2018 M3 LR DM. I used 3700 kWh to get there. My previous car, a Mazda6, got about 30 mpg. If gasoline has averaged about $2.40 per gallon this past year (in my area, which is southern Indiana and not California -- the savings I'm about to show would be quite a bit better there), then in my Mazda that would have been 467 gallons of gas, or $1,120. Just for fuel.
My electric rates are .1038 per kWh. So 3700 times .1038 is $384. Just for fuel.
That's $736 saved, to be used for something other than fuel. Advantage: Tesla Model 3.
Life is good but it's better in a (cost-saving) Tesla.