> Domino's and lots of other places do it, but they probably aren't paying $15/hour and they also have one central location and more predictable demand.

One thing to note about Dominos is that people pay at the door, so they would need to look the delivery guy in the face as they stiff him on the tip. Not required for the delivery apps and fewer people tip there.Because people tip, you can pay lower wages.

I had a relative who worked as a Chinese food delivery guy for a while and he did it exclusively for tips. The restaurant did not pay him at all.