> we haven't expanded into space because we don't need to? What's the benefit?
Access to resources. A sense of adventure. Learning.
The only argument for space is because you're so set on capitalism that you'd rather destroy the earth than stop trying to continually grow profit. If you're that sick and deluded, then space gives you a way to escape the consequences of your own foolish hubris.
Which resources are cheaper to get from space? I’ve only ever seen hand waiving arguments, never any math.