That's a pretty narrow definition of what's productive. Information is capital. Being able to link up a customer with an on-demand driver adds a lot of value into the system.
You're right that middlemen are productive in the generality.
But
> Being able to link up a customer with an on-demand driver adds a lot of value into the system.
This is only true if the driver's rates are something the customer is willing to pay. Finding that match is the primary job of a middleman; a lot of American services matching this basic description gloss over that part of the match entirely.
