How can a diode defend the coil during transistor cutoff?

[truesearch]

Before the days of readily available, cheap semiconductor diodes one way to protect circuits, relay or magnet coils and people from high induced voltages at switch off was to have a resistor (a light bulb was common) permanently connected across the coil.
This provided a path for current so that the induced emf was kept low.
The disadvantage was that, unlike a diode, current was always flowing through the protective component and this was wasted energy.