A generator is one option, solar panels or just regular battery backups are another option.
If the grid is up but overloaded you can also just charge slower, which for 99% of people will work.
At least you can charge your car at all, if there is an actual power outage, the gas pumps won't be working at all, and even if they are, it requires so much infrastructure to deliver gas to the pumps that they won't be working for long.
Edit: since when did an expensive car equal easy to operate? Historically, the more expensive the car gets the more caveats to the operation there are.