Comment by tetromino_

The bags of garbage are a historical relic. The city allowed trash in bags during as an emergency measure during the 1968 garbage collectors' strike: the metal trash bins were overflowing and garbage on the street in bags was better than garbage on the street raw. The strike ended, decades passed, but the rules were never updated until the last couple years when the city has finally began strongly incentivizing, and in some cases mandating, bins.