I think you're being sarcastic, but the purpose of leaving the garbage bins outside is so that the garbage trucks can pick them up, as their contract stipulates that they pick up from the sidewalk and not from inside the (numerous) buildings.

Even in the suburbs, residents of single-family houses typically need to bring their garbage/recycling bins to the end of their driveways. I think the only time that this isn't the case is when there's a special contract for certain isolated apartment buildings or complexes where the rubbish is stored in larger garbage dumps for the sanitation crews to pick up.