The difference is, imagining that we can turn an existing technology into a smaller, portable, more effective version of itself is not far out of the realm of reality. In fact it would be incredibly naive to believe that won't happen.

AI, on the other hand, is not so simple, and to try to simplify it to that point is not going to create any productive discussion on the reality of AI.

The movies about these kinds of things are made to entertain, not to teach us about AI.