Look further back. The "one knob" concept was a reaction to tuned radiofrequency receivers of the 1920s and 1930s.[1] Those required the user to perform simultaneous, coordinated adjustment of three tuning knobs. The big advantage of superheterodyne receivers was that tuning only required One Knob. All they needed was a tuning knob and a volume control/on-off switch. That technology replaced TRF receivers, and radios became a mass-market product anyone could use.

[1] https://en.wikipedia.org/wiki/Tuned_radio_frequency_receiver