Uber tells drivers where to go, and when, if the driver agrees to do the work. Uber regulates the kind of cars acceptable, and regulates who does the work. Your Uber driver can't subcontract the drive to another driver.
Drivers can absolutely sub-contract. most choose not to in the US but it's the core of how the Uber Black business functions (a limosine company with a number of employee drivers) and is still how it meets demand in developing markets or in developing economies.
https://help.uber.com/partners/article/i-want-to-become-a-fl...
Uber regulates what cars are acceptable the same way an Ebay seller has to maintain some standards in their store. Similarly Ebay also verifies that you can even be a seller on their platform, just like Uber does with background checks, DMV checks, etc.
To your last point on subcontracting...I'm not even sure thats part of being a contractor or employee so its neither here nor there.
> Your Uber driver can't subcontract the drive to another driver.
Even if their ToS does not allow it , it's not the law
