Speaking of early radio history... Tesla always claimed (incorrectly) that radio waves travel along the ground, not across the sky. This was actually a very forgivable mistake at that time. When Marconi first discovered skywave propagation by sheer luck, this finding puzzled all physicists (who all believed it's restricted to line-of-sight propagation).

Before people accepted the correct ionosphere explanation, great physicists Arnold Sommerfeld and Jonathan Zenneck gave an alternative solution. They solved Maxwell's equations and found a propagation mode exists at the interface between air and a lossy ground, known as the Zenneck surface wave. And this wave is not electromagnetic radiation, but more like a guided wave, with 1/r attenuation (a low loss), and NOT the inverse square law, 1/r^2. And one time many believed it explained Marconi's result

Today it's usually thought to be a purely theoretical result and impractical (though there are some fringe researchers who claim otherwise), so its existence is only remembered by E&M theorists but not many engineering texts. Some even (incorrectly) rejects its existence due to its messy history.

It's my guess that Tesla had also seen and believed these results, if so, his global wireless power transmission plan became natural.

See: Collin, R.E. (2004). Hertzian Dipole Radiating Over a Lossy Earth or Sea: Some Early and Late 20th Century Controversies. https://zero.sci-hub.se/1852/5e001629a9d60221aba62f86062aab75/collin2004.pdf #electronics