[cjhveal]

Probably to satisfy legal duties. Someone, landlord or municipality, has a legal obligation to ensure that waste is dealt with regularly and appropriately. If they contract with a third party, they have fulfilled that legal obligation, and even if the trash piles up, the question becomes why did the third party not fulfill the contract. If the responsible party leaves it to scavengers, they are assuming liability should the trash pile up. Ultimately, this legal service is why the "legitimate" business isn't providing the exact same service as scavengers, though I agree with you it is less efficient at waste removal.