E.g., around the time De Forest invented the triode, Reginald Fessenden was inventing AM radio. "AM" stands for "amplitude modulation", wherein you vary the strength of a radio signal to conform to a wave form from an audio source.
Fessenden's solution to the modulation problem was admirably brute-force: Generate a radio signal using a really fast (and heavy) alternating current generator and modulate the generator's output with a water-cooled carbon microphone!
In 1904, he got his alternator from General Electric. It was a 50kw model, designed by Ernst Alexanderson, operating up to 100khz. It was more powerful and a lot quieter than the spark-gap contraptions he'd tried earlier (with limited success, however). And, on Christmas Eve, 1906, it sufficed to produce the world's first AM radio broadcast.
De Forest's invention paved the way both for better ways to generate RF and better ways to modulate it.
You are quite correct, of course... As a youngster in the late 50’s I read about De Forest, and as a budding engineer, he was one of my heroes.