I hate this thread, but feel the need to point out that using Black Sabbath as evidence of metal's popularity isn't a great example. Sure, they're metal, but they're nothing more than hard rock to the general public. Not to mention that these people don't care about Tony or Geezer, but only Ozzy. The Dio era (or others) mean nothing to them.
Also, Hot Topic has changed a lot of the years. It used to be ok, stocking a lot of melodeath and metal around the same popularity. Then, it became pretty bad, going to mainly Metallica, Iron Maiden, etc. Then, it was awesome, and they started stocking Kreator, Sodom, and Destruction stuff. And now, it is worse than it's ever been. Last time I went to one, I could only find Metallica and not Slayer.