If the government wanted to impose a rule that would cost the retail gas businesses very little, but would be of immense value in SHTF situations, it would be that every new, or rebuilt, gas station had locked panel/junction box (the name doesn't matter) where you could throw a switch that disconnected the pumps from local power grid, and connect them to a portable generator. I wouldn't even require a generator, Just a safe way to hook one up. Gas pumps shouldn't draw a lot of amps, so a hardware store generator should be enough to get gas and diesel flowing again.
If the pumps need 240 volts many consumer generators can’t accommodate that.