I think we're returning to CLIs mostly because typing remains one of the fastest ways we can communicate with our computers. The traditional limitation was that CLIs required users to know exactly what they wanted the computer to do. This meant learning all commands, flags etc.

GUIs emerged to make things easier for users to tell their computers what to do. You could just look at the screen and know that File > Save would save the file instead of remembering :w or :wq. They minimized friction and were polished to no end by companies like MSFT and AAPL.

Now that technology has got to a point where our computers now can bridge the gap between what we said and what we meant reasonably well, we can go back to CLIs. We keep the speed and expressiveness of typing but without the old rigidity. I honestly can't wait for the future where we evolve interfaces to things we previously only dreamt of before.