I think you make a good point. If BCI is limited or impossible then then the future may be very intricate - perhaps Dune-like in the sense that natural human capability becomes the measuring stick for achievement. Humanity will become a beautiful anachronism like mechanical watches or bonsai trees or something. We will become dedicated to the art and science of our own self-cultivation.

On the other hand, If BCI is possible and useful, life will be miserable and we will borg ourselves just to keep up with the cost of living. We will be brains in jars on server racks solving captchas or something. We'll be the solution to AI hardware prices- the paperclip machine will be capitalism and nature itself.