In this 6 purposes of Vacuum Tubes Video, what does "Generators" mean?
Yes HF generators used high power valves in a linear mode to create high current RF generators for tin plating, AM radios in the multi kW range, Now they are megawatt generators for radio AM and FM radio.  This genration uses high DC bias current in high voltage oscillators that resonate the load from DC to convert to RF AC with about 50% efficiency or less.  A microwave oven today uses a 1-2kW Magnetron tube for generation of power.  https://en.m.wikipedia.org/wiki/Cavity_magnetron