If there's one copy of a book in a town and its your cherished thing, that's fine.

If you're the only person in town with a copy of a library's worth of books and you aren't willing to share any with your community to borrow, you're allowed to do that, but you sound like someone who doesn't really want to be a member of a community.

In that case, it's all on a case-by-case basis.

There are some books that I would just give away since they would be taking up space, there are some books that I wouldn't mind lending to anyone at any time, and there are some books that I would only lend to someone that I know personally.

Live together or die alone. We can be a civilization one day, or we can keep being monkeys throwing sticks at each other in the dirt, but with smartphones and smog.

Sure, but we were never meant to be a global one, I'm perfectly fine with being a part of a certain tribe of monkeys that is ready to throw sticks at another tribe for our way of life.