Most literature pushes the view that we as librarians must justify our existence in a radically changing information world. I see this as a negative starting point, especially in public libraries.
We are there to add value to information available to users, either current or potential, and that is what we have always been. Information is there, and always has been, and we augment access to it. This means our role is to stay in touch with all possibilities of access and dissemination, and being prepared for the needs and wants of our users. We must be trained, and willing to train users, and supply the means of access. This allows us to be innovative and creative, as we always have with the tools available to us.
Public libraries have a huge role in recreation, which will always have the book dominated fiction component. We provide possibilities to users, such as book groups and good readers advisory service, and we have quality stock available. There has to be a "just in case" component in collection management. The same is true for elements of our non-fiction - the stuff that doesn't rely on updating such as biographies.
So, I don't think we are fighting for existence, we are doing as we always have and being aware of what is possible and presenting it in the most accessible ways available.