That's the only new path that metal is creating atm. There's nothing else out there that hasn't been done before. It's hard to do something new in metal today, because like Llama guy said, bands are already playing as fast and as hard as they can, Black Metal has hit it's peak and is already about as extreme as the genre can get. Where do you go from here? All progression has led up to this time where it takes something absolutely extraordinary to break the mold. The only thing that anyone has come across is the changing time signatures, extreme vocals and such that metalcore is doing.
Tbh, this is not only a problem with metal, but with everything in the world. Have you noticed the surplus of remade movies and movies done off a book or another form of someone else's ideas in the past few years? Creativity is coming to a stand still at this point in human history, and as depressing as it is, it's really hard to see things getting better, because what hasn't been done before? It takes such a dramatically radical idea to even be considered creative anymore, and there are very few of those types of people in the world.