Not just some reason. The reason is that we have no facts to suggest otherwise. I know you know that.

The irony is that Kuttner probably knew more hard science in his day than current science-fiction writers know today. You tell me. Young people probably watch Foundation and believe Asimov was a science fiction writer. In those days, science ALWAYS came first. Or if on social issues, PHILOSOPHY, or deep works on sociology, psychology, etc.

Today we have science as religion, as aspiration, as status. Real FANTASY (and not in a good way) Stuff is made up. Elon Musk makes up hyperloop and everyone believe it will work. If Asimov would have written about such a thing he would have said the materials used to construct it were newly discovered materials. Materials that keep their strength in all temperatures and all shapes and stresses.

Today, it's aways, "we'll figure it out tomorrow." With no evidence that any real progress has been made. Rant over. Hope you're well!