Noise is only due to carelessness -- with a good layout, and with enough filtering and shielding, you can use almost anything.
It helps that early designs were very simple: few transistors, so that the total gain at high frequencies was still only modest. Transistors weren't terribly fast either, power transistors especially. This prevents the generation of high harmonics, so that shielding and filtering in the 100MHz+ range isn't needed, or even 20MHz perhaps. Keeping switching edges low, with resonant designs, always helps, too.
Nowadays, transistors with fT in the GHz are common inside controllers, so that, if nothing else, the controller alone may be responsible for content in the 100s MHz range. Modern transistors are also freakishly fast, with silicon SuperJunction types having performance in the 100s MHz, and GaN types even faster still! This requires the designer to be even more careful yet; on the upside, the increase in frequency allows reduction in component size, so that a filter with good stopband attenuation at 100MHz+ doesn't have to be complicated.
Tim