[ChemicalWarfare]

I highly doubt that any of the bands you mention in the 2nd paragraph will sell out an arena by themselves. Even in their heyday godsmack,a7x, disturbed would maybe fill a large club. But then once the "real metal" picked back up 10 years ago or so these bands lost their appeal to the old school slayer/pantera audience just because there were other "options" available. Same goes for the younger deathcore/metalcore crowd (with a7x managing to stay afloat in that pool but nowhere close to where they used to be popularity wise).

[serge2k]

The black keys are pretty mainstream compared to the others.