The entire value of Uber was the app hailing (in my opinion) - the cab companies could have leaped on that but didn't.

Same with the bike rental things like CitiBike - there should be roving vans throughout the city moving and balancing the slots based on usage. They have the data, use it. They could even offer to "fix" problems (e.g., arrive at the train station and there's not a slot available? CitiBike will send a vehicle to get you to your destination within reason).