The books in the library are still someone's property, even if that someone is a city or a church. If I decide to start a library tomorrow, can you tell me what books to buy with my own money?
As for your "could be" argument... Looks like we both agree that humans like they existed in history and exist now are not capable of of such "could be". I think it's indeed called "communism", and it failed everywhere it was attempted. Moreover, its failure produced human suffering and death beyond anything else humanity experienced before.
(Some say it has never been attempted properly. May be. I don't care.)