UberBlack drivers never signed up to accept UberX fares. That wasn't part of the contract, which is why so many feel cheated, an equivalent of a cable company selling you a promotional $19.99 rate and then upping it to $79.99 once you bought the equipment.

> To bring supply back in line with demand, some drivers who used to drive Uber Black should either leave or downgrade

Sure, or some passengers who used to want a cheaper UberX but find it unavailable should either resort to alternative methods or upgrade to UberBlack - market equilibrium can be found in either direction.