Ouch. I forget how mad California is. No wonder rooftop solar is so attractive.
Peak rates are ~20¢/kWh here, but there is a largish fixed per-customer monthly hit for various debts and obligations. And people regularly complain we're the highest cost province in Canada. 70¢/kWh (in BIG dollars!!!) is just insane.
Well, no. It depends on all the variables. It may or may not be cheaper.
Your case is quite extreme with nearly free electricity! Sure, EV will be cheaper to run for sure.
Here in California with overnight rates around 30c/kWh and day rates over 70c/kWh, the numbers come out different.