Literary theories do not necessarily come to an end in a highly definitive sense. The reason we could say this is because some will still ascribe to far older theories. However, while there may be some contemporaries who legitimately believe in the ideas spouted by the New Critics, they have certainly decreased. Theories, in general, come and go because the ideas within them lead to new ideas that branch out from them. Many theories are responses to existing theories, and so we may be several theories detached from some much earlier theory, but the influence of that older theory still persists.