What I hope will happen is a Red Hat-style company emerging that will maintain an open-source car sharing app/webservice. They would sell support or host each

What I hope will happen is a Red Hat-style company emerging that will maintain an open-source car sharing app/webservice. They would sell support or host each city's car-sharing service for a fee, or just let people set up their own. This way, cities could run the service at cost (or maybe even subsidize it) and drivers would take home more. Or they could use the revenue for the city instead of having it leave the local economy.