That may well be true.
To throw a monkey-wrench into the argument, however, I would add that in the radio/electronics field it seems as though some modern manufacturers could take a lesson from the past. Techniques which were once commonplace seem to have been forgotten.
Look in some equipment now and you'll find AC wiring from power transformers (both primary and secondary) running on separate conductors not particularly grouped.
In the old days, the effects of EM fields from such wiring were widely understood. Look at the way AC power was wired to the filaments in old tube equipment, for example, and you'll see a tightly twisted pair run close to the chassis (they didn't use the chassis as a return path, even though one side of the filament wiring was grounded to it).
Keeping the EM field from the filament wiring as low as possible was important when very low-level signals are being carried on adjacent wiring.
