Unlike Facebook, Uber is easily replaced. I can't convince my friends to change to a Facebook competitor, but for Uber I don't have to. I don't lose out by using an Uber competitor. With Microsoft in the 90s I couldn't share or read documents if I used a competing OS. I literally had to use Windows.
Right now, Uber is paying lobbyists and lawyers squirming around the issues with braking taxi laws, labor laws, tax laws etc. And they are paying for marketing to teach us to order cabs using apps. And then, local competitors can make apps that are as good and the business model is easy to compete with.
If I travel to London I might not know what the local competitor of Uber is called and I may wanna go with Uber or a conventional taxi. But back in my city, Uber is just one of a bunch, soon one of many. That's, by the way, a difference from AirBnB who is only used by people who are out of town.