While switching to the simple option may help the likes of Uber defend themselves on the legal front, the switch may not be that simple to implement and will be costly on the business front (if not making them cease to exist). First, the switch will likely lead to an increase in ride fares and a decrease in user experience. Second, it will be increasingly difficult for the Uber's management to justify its massive operating losses, when they cannot say to their investors "hey, we can always increase the price at will".
