In my village, charity spontaneously arises, whether in the form of a local food bank, fund-raisers for home fires, or serious illness, not covered by insurance, and so forth. But, the larger the town/city, the less frequent the spontaneous local charity. So, while not disagreeing with your thesis, I revert to the bed-rock principal of subsidiarity in relation to organized assistance for those in need. If it doesn't arise locally, as empirically determined, then use the larger entity.