Musical Clone Machine

]I've been listening to song samples on Amazon, and I find myself thinking that some of these albums are kind of nice, but I feel like I've already heard them by other, better artists.

For example, I heard samples of a Bullet for My Valentine CD, and it does that nice thing where they mix rock screaming with melodic elements, but Red, Skillet, Three Days Grace, and obviously Linkin Park who (in my opinion) perfected it, all do it better, so why should I buy this lesser though similar music?

I listened to samples of something else – I can't even remember what – and it sounds like yet another Blink-182, Sum 41, and/or Offspring crappy clone. Why can't they be more original?

I realize I'm supplying multiple examples of similar things that are good, so maybe it's just that some artists are able to stay within the line of being inspired by something to create something that's different enough so that you can still uniquely identify them, and others are leaping over that line and just making crappy copies of things. I think some of the "crappy" ones might actually be decent copies, but they're just not good enough; perhaps "mediocre" would be a more fair word.