I think that you would find that school libraries are quite different from public libraries. School libraries are geared towards the curriculum, which means that they are devoid of almost everything written for an adult audience. Want a good book on electrical engineering, a deeper discussion of history, business databases, international newspapers, or just about anything considered too touchy for developing minds ... then you need a public library. School librarians (when they can afford to have them) also have more specialized knowledge than public librarians. Public libraries also seem to be an informal sort of social services these days, especially in the cities. Need help finding a job? Are you homeless and need to get off the streets for a few hours? Do you need computer training or literacy training? You'll probably find better help at your public library than a proper social services office (and these generally aren't the type of people who you want to pull into schools anyway).

Even when it comes down to people who use libraries to make money, such as businesses using databases or periodicals to do research, I'm confident that you'll find that libraries are a bigger boost to the economy than doing nothing and far less of a burden on the economy than forcing everyone to make the own way.

Remember, sharing is good.

Maybe small city and town libraries are different.