I volunteered at my local library and they were struggling at times in terms of man power. I think they had too much responsibility but the budget of someone who handles books only.
Books, Internet, Movies and music, Free lunch for kids under 18, Some computer classes occasionally, Meeting areas for adults, Club activities for kids, Occasionally local cops organized "Pokemon Go with an Officer", magazines, subscription to many newspapers, etc etc.
Most people don't think of volunteering in libraries either. They were back logged with shelving out the books that hadn't been checked out in a while. Without doing this, they can't really keep getting new books. Trying to manage the CD/DVD is also more hassle than you think. You have to regularly clean it and get rid of the ones thats too damaged.
My college library is decent too. Nothing like the public one. Especially considering the college one probably is better funded.
A lot of people from a lot of different age group depend on the library for the internet though.