You're a mother carrying groceries and a kid and you have to walk ten blocks. Is it as essential as medical treatment? No, but it's a substantial degradation of your quality of life if you get priced out of it. I think the political attention on the topic speaks for itself as to how essential the public views it. And we're not just talking about Uber here, we're talking about taxis in general: if Uber drives taxis out of business by undercutting them during ordinary circumstances, there won't be any around to undercut Uber during a surge.