Gas station pumps run on electricity. When the power goes out, gas does not get pumped.
That's a business decision. While stationed overseas, we powered the fuel pump from the battery of each vehicle being filled.
Stateside, commercial gas station owners don't want to put in generators because they can't recoup the costs and don't trust the gas jockeys to not burn the place down.
Most people living in disaster areas have extra gas on hand. How do you have an extra can of electricity on hand?