When I started school back in 1975, my school had a very small library. Books were scarce. Students went to the library once a week to check books out and back in. Rarely was there time to teach anything other than the basics of card files and Dewey's Decimals. The high school library was larger in the mid 1980's but there was no scheduled time to attend and definitely no teaching in that space by our librarians.
When I came back to my hometown school to teach in the late 1990's the library was still small, books still pretty scarce but the librarians would teach students lots of different things, usually revolving around books and research. The library also had videos for teachers to check out.
At some point, due to the state's requirements and an emphasis on reading in our building, the number of books in the library grew much larger. Books became much less scarce. Computers have been added to the library, allowing students to have access to sites on the internet and for content creation.
At some point in the future, hopefully soon, students will have internet capable devices that allow them to access digital media. The library as a place for students to access content will be much less necessary than before. This will also mean the need for the computers will be minimized as well. So, what will be the purpose of the library then?