Unfortunately I agree.
Sadly 1 is pretty unlikely, Its difficult to imagine anything of enough value that only exists in space
2 could happen, but as a society we are moving away from high energy density technology like nuclear because there are better options on earth. Rockets already make pretty efficient use of chemical energy. Other schemes like space elevators seem really improbable. (I hope I'm wrong).
So 3 seems the most likely.Eventually maybe some space-faring race will discover and catalog the ruins we left behind.