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