It's worth noting that energy transfer rate is not the average limiting factor of pump turnover time at gas stations. A significant portion of people are also doing some combination of going to the bathroom, buying snacks, washing their windshield, etc. And I'd be willing to bet most gas stations have idle pumps the majority of the time. You'd have to do a real study of a station to determine if replacing pumps with fast chargers would serve enough cars or not.