Unsure what you are basing this notion on, bro. Are you talking radio play, hits or...? I'm a huge fan of NIN but Reznor, as good as he is, has nothing on Soundgarden, imo. Forget Cornell for the moment and listen to Thayil play guitar. I don't recall NIN ever having anyone like Thayil in their line up. Take away Tom Morello (Rage) and few bands of this genre ever have.
And the guy that asked for Metallica. Just...no. Why do I feel I should always add a trademark logo to the name Metallica? I've been back stage with the band ..once (Honolulu) and would never accept that invite again. Stuffy ass, pretentious, no fun, corporate pricks. Each with their own entourage and limo. It sure didn't hurt their profits, but from that night on, I vowed to never play them on air again. Which is a ton of fun because their fans have to be the most demanding, obnoxious and rabid of all fans. I basked in their hate mail and death threats!
BTW, Monster Magnet embarrassed Metallica that night. Exit light mofos..exit light.