When I was younger, stores gave out paper bags. And we later used those bigger ones from grocery stores to line the kitchen trash receptacle.
Then plastic took over. Some of those ended up lining smaller trash receptacles. Now plastic is banned and the retailers demanded that the law include a charge for any paper bags provided. If I remember correctly, it was because they cost more than the plastic ones did.
As far as gasoline in NJ, the story I always heard was that most stations were independently owned and their association fought self-serve as it would give a cost advantage to the larger corporate locations. A large station would need one attendant for say 20 pumps, while Joe’s gas station also needed to pay one person for their two pumps. Same cost but much different volume of sales.
But many independent gas stations have closed up over the years, I think due at least in part to lack of garage work, which is where some made much of their money. So there may be a greater chance of self-serve becoming a reality one day, unless there is a strong outcry from the public to keep it.