The most likely outcome in the near term is that self-driving is an auto accessory you can order for a car. That's what the car-makers have in mind, and most of them are talking about shipping it for the 2020-2021 model year. In that business model, it's not a big money-maker for whoever sells the self-driving technology. They get to be a Tier I auto parts supplier, squeezed hard on price.
There's a lot of noise about "transportation as a service". Remember that Uber loses money, even after squeezing its drivers really hard and making them buy and maintain the cars. Actual "transportation as a service" is going to look more like car rental and Zipcar, and will probably come from companies that already operate fleets of cars. They already have "rent by the hour, day, week, or month". They're just adding "rent by the trip". Also, bear in mind that "transportation as a service" requires level 5 autonomy - no driver required - so the vehicles can move around empty to pick up a passenger. That's going to come a few years after Level 4.
Autonomous cars don't require car to car communications. They don't need to be "connected" at all. Chris Urmson pointed that out when he was heading Google's self-driving effort. From a safety perspective, it might be better if they're not connected. The enthusiasm for car to car communications is coming from the infotainment and advertising people.