Yeah, I'm not quite sure about people saying that metal wasn't what it was 10, 20 or 30 years ago, or that it is living off the last three decades.
People said the same thing about the 90s when it was going (and it was until years later that a lot of the now 'influential' albums were aknowledged, with the exception of nu-metal funnily enough, which of course is now so taboo we best not mention it).
The 80s were a different kettle of fish - metal was at its commercial peak and was really only just starting to form its own unique identity - people say it began in the 70s, but to be honest, it was just a way of describing the more new, heavier rock bands, like Van Halen and Kiss were considered heavy metal in the 70s but few would class them today because they do not hit into that indentity that was formed in the 80s.
Because metal formed this identity - granted that has evolved but only slightly - in the 80s, a lot will be compared back to those 'glory years'.
But a lot has happened in the last decade. Think of the whole post-metal/instrum-metal movement - who did take influence from 90s Neurosis, yes - but can pretty much be traced back to the work Isis was doing in early-00s - and it is a genre that has certainly become more atmospheric in its approach and continues to move further away from its sludge origins.
A lot of admittedly less viable drone and noise acts have also emerged and taken that sub-genre in new and interesting directions. Of course this is music that has less to do with the more traditional leanings of music and is also probably unlikely to gain the kind of commercial success that the more 'trad' proprieters of metal are always going to receive (mainly because they have a cross-generational appeal, for example the thrash revival or even the development of, say, death metal)
Also, as much as I dislike the term, 'prog metal' has certainly changed a lot from simply being power metal bands with concepts or long songs. To think that a band like Enslaved would have evolved to where they are since their beginnings in BM to what they have done over the last decade is almost unfathomable.
I think a lot of people are trying to measure whether metal is still vibrant and creative in waiting for a big movement like thrash or black metal to happen but the truth is I think in this globalised world it won't happen. Think about it - thrash is associated with San Fran (and later on the Teutonic Thrash of Germany/Switzerland), and black metal with Norway. These were very localised movements, and this simply will not happen in a globalized world. There just isn't the isolation to develop a localized sound like that. As soon as a band is created, there is a demo up on myspace.
This all isn't inherently a bad thing, but it is far easy to stand back and say that all is rubbish and derivative now, when the decades before have had, well, decades of analysis in hindsight and diamonds in the rough have been unearthed that just weren't popular at the time but have emerged into something much larger (funnily enough, a lot of people forget that when metalcore emerged, it was hugely popular because it was laying to waste nu-metal with real metal only to become the nu-whipping boy).
Anyway, it'd be good to hear others thoughts on this kind of thing. Hopefully some of that stuff I just wrote makes SOME sense!?!?!