“Why hasn’t your society built self-replicating spacecraft?” could be a question similar to “Why do you keep playing video games instead of doing your homework?”

This is excellent. Also: we have the problem of science fiction fans predicting the future based on what looks cool for science fiction fans, based on what science fiction fans like, then finding clever justification after the bottom line was decided anyway, such as, having space colonies being a hedge against extinction events.

It would be really useful to try to empathically visualize the preferences of people who DON'T read SF, who think a fiction about spaceships, blasters and suchlike is downright silly. What kind of future they want? I would easily imagine one answer: send out robotic ships to haul from asteroids or foreign planets here everything we would want, while we ourselves sitting comfortable and safe at home.

Using only robots for unsafe missions i.e. everything outside Earth sounds like a fairly obvious thing a non-SF- fan would want.