Especially for Uber who can incentivize payouts in an elastic fashion as the available labor pool shrinks. Service quality might decline a bit as available drivers decrease...but Uber won't even have to explicitly go out and find "scabs" - they can simply temporarily surge pricing to entice some of the drivers who either aren't striking or who aren't as committed.
Difficult indeed to really cut at the heart of Uber in this case and really swing some leverage as organized labor.
Especially with the setback face in U.S. court.