These businesses are already unprofitable. So you probably couldn't have another DoorDash that pays its workers more. I suppose you could argue that some restaurants might have their own delivery services, or something. But that'd be tiny in scale compared to what these services are doing.
A tiny delivery service based around a local group of restaurants could easily have a fairer distribution of income and time consumed. Since the delivery service operates from about five or ten shops there's no "drive 10 miles to the pickup". Since the service is basically local there's no "take money from the poor and give it to the richer" - even the profits that go to the capitalists is still going to local members of the community who are making some money, but not too much to know what to do with. "Unprofitable" is relative.
Consider: restaurants often consider delivery to be a 'loss leader'. It's not a terribly profitable industry, maybe not at all profitable. A more limited service (unable to average costs over a large number of restaurants and customers) is going to be even less so?
Right, but as I said, the scale of these local delivery services is much smaller. Even if we accept your premise that each local job would be better (which i'm not sure is true, but i'll grant you it), there would be far fewer of them. It's not obvious to me which is better: A lot of bad jobs, or a few good ones?
