Schools in poor towns don't have multiple levels or basements or even extra storage rooms. What you see is all you get.
If there is enough space to have a room full of books, it would be better used as a publicly accessible set of stacks. The only real reason to have a librarian-only room is for books that are rare and valuable.
Society is completely overloaded with a vast surplus of commercial property. Something can be done
As I implied elsethread, the solution for that is better funding.
Someone needs to take up Carnegie's mantle and finish the job which he began.