Thermionic Emission Conservation of Energy
I was mistaken on the principle that governs vacuum tubes. It is not that the signal is being amplified by thermionic emission; rather, the radio wave is being used as a gate to allow or block electrons from being received. Thermions are being emitted from a coil using electricity, emitting at a higher current, modulated by the radio wave as a control grid (preventing or allowing the thermions from being collected at the anode).