What do you mean by "whenever you need it"? Are these situations where taxis are unavailable due to demand? If so, that seems to back up Uber's point that raising prices during high demand times creates a reliable transportation system. It seems like the point is to incentivize people to look for other options (or to wait) when demand is at it's highest, so that it can always offer a ride. The price for that ride might be higher, but it's there. The price for the taxi (in those high demand times) might be lower, but if it's unavailable, that price doesn't do you any good.