How complex is the librarian's job?

Having worked as a teacher for many years, I know the huge learning curve that we have all been on in relation to advancements and changes in technology. I didn't at the time think much about how much the librarian's skill set would be challenged as well. How important it is to keep up to date with the technology kids like to use these days, to integrate it inot our practice and to maintain a positive relationship with the IT people in the school.
It's also interesting to read about school libraries, usually in USA, whose funding is dependent on proof that the library program is making a difference to the  school's outcomes. Shouldn't we all have to be accountable in some way? Perhaps not for funding but just to justify our existence! I don't kow that this has happened in the past - at least not in the schools I've worked in.