Not all of it, but the concept that metal was 'too rebellious to control' is somewhat flawed, Metal and even Punk have corporate equivalents (though, much like with Rap, there are those who would argue that the connection is in the name used to describe it, and in no other way are they similar - that's a discussion for another time though). I don't think it's so much to do with the music as the costs required for production, studio time for 4-5 band members, instruments etc is expensive for rock bands with guitars and drums etc, which is what the traditional metal audience expect, but with Rap and Pop you only have one person to pay, you can produce the music on a moderately powerful PC, a lot of pop music isn't even composed, it's the studio equivalent of Fruity-Looped, and in metal, if someone used an autotune to fix a crap voice, there'd be riots.
The simplest answer is for people to simply stop buying corporate production line music (see the UK's current News over 'Killing in the Name of...' by RATM), and eventually, that will happen, but for now, let's hope the UK campaign is at least enough to teach Cowell that the public is getting increasingly sick of wishy washy music and rather poor regurgitations of songs that other people wrote several decades ago.
