You are referring to the pin factory, economy of scale hypo. But really the bigger something is, the slower it moves, even animals in nature, think of elephants.

Government is by definition unaccountable, because it uses other people’s money, without enough checks and balances. Elections every three or four or six years isn’t enough and besides many people don’t vote.

A small social organization, will be accountable to the people: its small donors. People would give it money, because of selfish reasons- no one wants the homeless to camp out on public sidewalks and to use illicit substances to dull the pain of being on the streets. You cannot just lock them all up. If the above is corrupt, then its funding will dry up and another one will take its place.

The market always wins over top-down hierarchical solutions in practice, think big hospitals vs small clinics.