In Ireland, I remember the petrol being sold on the street in front of newsstands. It makes clear the reason for having the gas cap on the left side in Japanese and British cars, because people would just parallel park and fill up. I imagine those locations are rare now both for flow-of-traffic and environmental reasons.

In the US gas stations used to be very full service. For the price of a tank (and tip) you would get your radiator and tires topped off, windshield cleaned, etc. There were probably a few old groceries that had a couple pumps but the full service stations quickly became popular. That ended with the oil crisis and stagflation, and self service became the norm, except in a few holdout states like New Jersey, where full service was the law.

The sad result you mention (which is good for consumers, perhaps bad for the environment) is that commodity pricing and loss-leader mentality has made gas worth selling at a small loss to get people to buy high-margin items in the store. QT has cheap gas and expensive sodas.