Metal evolved quite a bit each decade from the 70s to the Ots, but now each newly formed metal band simply picks their favorite style from one of those decades and emulates that sound to the best of their abilities. A lot of those old bands are still around, and they all still sound the same. They trade musicians like baseball teams trade players, but they don't bring their old style into their new band. They just learn their new bands style, while their replacement in their previous band learns that bands style. They all have like 20 albums now. If you're lucky, they still have the same vocalist.
