[bdamm]

Or would we have transitioned to highly directed laser pulses, or perhaps using a medium not yet discovered? Since we are still fumbling in the dark about fundamental physics, having no grand unifying theory between large and small, or even much progress in understanding gravity, it is entirely possible that we wouldn't be using radio because we found something much better.

[tsimionescu]

A small note: a Grand Unified Theory is not a theory that unifies the large and small (presumably you mean something that solves the measurement problem in QM), it is a single theory that unifies the electro-weak force and the strong force, leaving us with just two fundamental forces: the unified one and gravity. Solving the measurement problem is necessary for having a complete picture of the universe, but a GUT is not - it is logically possible for the universe to have several different fundamental forces; but it's not logically possible for the macrocosm not to be reducible to the movement of its constituent particles.