Yep, that was in the 1960s. I went to work at a full service station as you describe when I turned 16.(1970) We washed windows, checked oil, checked tire pressure if asked, fixed flats, sold tires, batteries, wipers, belts and hoses and did minor repairs. The station was open 24/7 365 days a year. The station also sold more beer than any place in town. (even after midnight and on Sundays - not legal at that time) LOLI remember that myself. That would have been in the 1960s.
Then one day Dad went to get some, and the tank wasn't there any more.
Talking to the station owner - you remember those stations. 2 bay garage, 4 pumps, fix your car, check your oil, and wash your windshield - the reason stated was evaporation.
Station owner said he lost more to evaporation than he sold. Couldn't make any money.
I remember when the first self-serve station opened in town and sold gas a little cheaper. People thought that would never catch on! Progress?