The reason why us broadcast engineers (the people that actually ordered them for radio stations) loved the 414s was the stainless steel cable and the jack on each earpiece. Jocks could trip over them and the worst that would happen is the jack on the cup would pull out. These things were near indestructible and had a great sound. I can't remember a pair getting so bad that they couldn't be used. Sure, some of the pads needed replacing, but the mechanicals or electricals never failed. One can still find some in use even 30 years later at some stations.
They also came in a 600 ohm model that was perfect for tapping on to feeds without dampening them, though this was more of a special order set and used by engineers.
Hell, if I could find a NOS pair I'd buy them.