Unlike eBay, Uber is courting business to use them, and considering how much Amazon is pushing the same day delivery (as well as Google and others), Uber does have a rather unique position in capturing quite a bit of that market...
More importantly, if you think of people as cargo, I think Uber is now one of the ten top delivery companies in the world. Swapping over their drivers from passenger to package delivery isn’t that hard of a swap.
That said, this is yet another tech company money pit. I’d save my money to buy the pieces when they go bust.