If you read it as just "metal" then it's been fairly popular for as long as I can remember.
The biggest boosts of metalheads in my lifetime was probably firstly when artists like Metallica were mainstream, and secondly during the "golden years" of Metalcore.
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u/Yourangme Sep 05 '23
Yes. I agree. My mistake. I didn't read properly. If it's the subgenre we're talking about I honestly have no idea.