Well, golly gee whillikers, they probably would. And yet, these guys play show after show, night after night, on tour. I wonder how that could be?
Could it be..........
TALENT ?
Pretty much. Its using proper technique, and proper warmups. If you don't warm up right your voice can be shot after one night.
There are a lot of crappy growlers out there. But there are also a lot of crappy singers. Crappy growlers are ones who can growl about 2 notes, and thus stick to the same vocal melody in about every song. Note, that they tend to belong to bands that found one riff they like, and then wrote 10 songs using that same riff.
I prefer growlers who can switch up the sound of the growl, various notes, and still know how to write vocal melodies for growling.
And if you use piss poor technique you get what happened to the lead singer of Avenged Sevenfold during the recording of his second album (or was it on tour?), where he destroyed his voice to the point that he wasn't sure if he'd be able to talk again. But, he regained it, and also ditched the growls somewhat on the latest.
James Hetfield also lost his voice (thrash vocals have some 'growl' elements) during the recording of the Black album I think (okay... maybe he wasn't using his 'thrash voice' during these recordings).
Angela has talked about the issues she had when she was losing her voice. What tends to happen is either tears in the muscle, or nodes. They can be surgically removed/repaired, and like her, if one is smart, they go to a vocal coach/vocal physical therapist, to learn how to take care of their instrument better.
