The thing is that every delivery service, or rather every service that has a human component in the supply chain, will have a significant cost to it that cannot

The thing is that every delivery service, or rather every service that has a human component in the supply chain, will have a significant cost to it that cannot be mitigated by going open source. Indeed the big cost for Uber and ilk isn't the technology cost per se, but the cost of human power (an issue which was incidentally raised to me by the COO of one such platform). And then as you mentioned, the costs of policing said platform so that it isn't used for illicit activities or sex.