I believe the 100lb gorilla in the corner of the room is the fact that we are witnessing an unprecedented push by the global executive for self-driving cars. The speed with which they - and their cousins autonomous trucks - are being ushered onto the world stage is breathtaking when you consider the legal, insurance and sociological implications. This suggests that there may be an ulterior motive involved, which could relate to the over-riding need to deal with chronic urban pollution, vehicular logjams and most importantly climate change.
What does this have to do with Uber/Didi/Lyft et al?
Well once these vehicles become commonplace on the road, the next most logical step is to introduce autonomous cab services, at a price and convenience that destroys the rationale for urban commuting. Whoever has the technology in any large population to supply an autonomous cab service en masse, gets to potentially grab a huge chunk of a billion (trilliion?) dollar pie. These door to door autonomous buses/cabs could literally transform the transit landscape. Already Uber is trialing an autonomous service in Arizona, it won't be long before we see more happening on that scale. The stakes are absolutely enormous long term.
Edit: Arizona/Uber - http://spectrum.ieee.org/cars-that-think/transportation/self-driving/uber-could-be-first-to-test-completely-driverless-cars-in-public