Do we still need the system life cycle?

Since the dawn of software systems the development process has been dominated by the traditional system life cycle. This is a route map, onto which a software project fits more or less comfortably, and which prescribes the stages through which such a project must pass on its way from being merely an idea in the customer's mind to implementation and delivery. It is true that, in recent years, techniques such as prototyping and the use of formal notations have been developed which seem to encourage a move away from a rigid life cycle approach; yet software projects based on these techniques seem to be significant more for the fact that they do not follow a life cycle pattern rather than that they do introduce a new development framework.