In California the public utilities and state officials are warning about using electricity between 4-9pm. They are even running ads on TV suggesting people not turn their air conditioners or run laundry during these hours.
Now imagine all the cars parked in driveways and garages, they can’t start charging their cars until bedtime? In a more ideal world the cars would be smart enough to know when is the most efficient time to charge. And they would also be faster to charge and easy to plug in. That last part may be true but people can get lazy. Like, sometimes I forget to charge my phone at night, wake up with a battery low warning. Annoying because these new phones have battery charging regulators - takes hours to fully charge.
The electronic to charge when power is available is doable.
But then, you may wake up, run to appointment, and car is empty, because there were never enough power.
Charging faster - not so much! You need high Voltages (dangerous, expensive insulators) and high currents (expensive, fat coper wires).
That Tesla supercharger is about as fast as anything ever will do.