Do you like unpredictable song structures? There are plenty of bands that can satisfy that lust for you if you get bored with the same old 4/4 no-tempo-change, no surprises metal. And you don't need to dive into avant-garde über-technical territory to find bands that avoid predictable song structures, if technical music isn't your thing there are plenty of simpler bands that can provide the same enjoyment. You're just not going to hear a great deal of experimentation from any remotely popular bands. You're not going to hear anything different besides chugga chugga from *some* old bands like Obituary or Bolt Thrower that are still putting out records, assuming you listened to these bands. I hate "metalhead culture" as much as the next person, I don't really associate myself with average metal listeners because outside of some popular bands I do like I don't share very much in common with most.
Sure, there is no "big thing" happening in metal nowadays(besides metalcore, which is bleh and only provided 1 worthwhile band in it's 10 years of existence and hundreds of offspring). But I ask, why must there be a new revolutionary "scene" or trend in order for bands to be enjoyable and worth seeking out? Frankly I think that's nonsense, I don't know about you, but the best bands out there (not exclusively in metal) are not the ones that you can easily label/group with another "scene" or regional area due to their sound, they're the ones that do something profoundly original and different from what everyone else is doing(and most importantly: is GOOD).
Say a band tomorrow wants to use bossanova elements in thrash metal(ok most genre fusions are gimmicks but you get the point), that could be an example, but as soon as there are 6 bands doing the same, what is the point?
Give me some Kronos, Spawn of Possession, Lykathé, Wormed, Gojira, Deathspell Omega, Sólstafir, Mithras, and so on. Bands that -though you could associate with whatever metal due to their approach- share absolutely nothing in common with any other band. They create sounds of their own, not follow some new doctrine in playing metal.
Over time I've grown to like different kinds of non-rock/metal-associated music. I like me some Bela Fleck, Pat Metheny, a handful industrial artists, Neil Young, and have recently developed a strong interest in early 80's british punk. In my experience the only people that really burn out of it are ones that listen to the same stuff for simply way too long(eg: Slayer and Metallica, I cannot count the amount of 30 year olds that said they used to like them). Lack of variety will kill anyone's interest in music.
I see where you're coming from, I don't think I'd still have much interest in metal if I still only listened to Megadeth, Dream Theater, Nevermore, Opeth, Slayer, Symphony X, Children of Bodom, etc.
That's not to say I still like most of these bands, just that listens are few and far apart, but still provide the same enjoyment they did when I first heard them. But to say there's zero innovation going on is totally ludicrous. It would be like assuming that all jazz is Holdsworth and Joe Pass and that it hasn't changed in 20 years.
Edit: To answer your question: I like the bands that I like because they make music that is fulfilling to listen to. My favorite bands/artists just happen to be mostly metal bands.
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I got the new DSO, and it's pretty boring, does anyone like this new approach?