The full serve station nearest to me is also quite small. Most of the space on the lot is occupied by a garage.
This is one of the rest stop gas stations on the NJ Turnpike; you can see how big it is by the spaces in the parking lot above it; plenty of room to gas up in the ‘wrong’ direction
Until a few years ago we still had about five full-service gas stations around here. All of them were actually repair/tire stores that happened to sell gas as well. There’s only one left here now. It still seems to depend mostly on repairs and tires, and if you want full service at the gas pump, it will cost about 40 cents a gallon more than self serve.