Small groups who can identify and contact each other can strike without a union. Uber drivers can't because Uber is the only party who can identify all of them.
Furthermore, scabs might sign up without even knowing they're scabs, or drivers might refuse to strike.
There would have to be some legal/organizational mechanism to force all current drivers to strike.
I was in an uber to one of Microsoft's collegiate CTF's, and when my Uber driver realized that means I knew (the very basics of) computer security he begged me to hack Uber and get all the Seattle driver's emails so he could ask them to strike.
He also tried to sell me on his cult. And told me to defend my servers all I needed was a fractal firewall that used the number Pi somewhere because if you use a number with (presumably) no pattern in it no one could ever touch you.
Wow. I often wonder how much creativity in our society goes untapped for lack accessible channels to filter and distill it. Thanks for seeing the potential value in his inchoate ideas rather than dismissing them for not being fully thought out.
One a side note, quite a few leaderless cults are well worth joining - not the social kind but the ideational/experiential kind.
This is absolutely, completely false. Both legally and practically.