My local Half-Price Books (a second-hand bookstore chain) has a vastly better selection than my local library.
University libraries of course might be a good exception to this rule. But your local public library should be a way to make reading accessible to the average middle to lower class family. And that means providing the materials they want to read - not what you think they should.
It's always going to be a balance for librarians. They don't get to operate in ivory towers disconnected from those local taxpayers whom fund them.