This is the key thing. None of this “trust a stranger” stuff actually works out. Uber isn’t actually a rideshare. It’s a professional driver. Airbnb isn’t a room in someone’s house. It’s an apartment rental. GrubHub isn’t someone who picks up your noodles when they pick up theirs. It’s their job.

The courier model could totally work the same way. You want someone to drive your package from San Francisco to New York? Someone will happily do that. The trick is they will want to get paid. No one’s doing this stuff basically for free as a favor or to help OP’s company show a profit.