I had a reply I was working on to your questions (everyone), but I just don't have the time right now to finish it and edit it so that it doesn't wind up just further confusing what I said earlier. To be honest, I think all the questions or rebuttals that have come up since were already addressed in what I said earlier, but they may not seem very clear.
Briefly though, I will try to answer a couple things:
First, it does matter whether metal persists or not, and not only to just those who want it to last. Those who do want metal to last, however, need to, in my opinion, come to understand what that desire fully means. And perhaps most especially, it should be noted that a continuation of metal in no way guarantees a continuation of "good" music.
I asked whether people wanted to see metal continue as a serious question. Additionally, I'm interested in the real reasons why people say "yes" or "no". Saying it's because you want good music is irrelevant and null though. If you want good music or you want more metal, that's okay, but don't imply a necessary connection between the two. There is none.
The desire for variety is a separate argument from the desire for something "new". At this point, there are plenty of metal albums to satisfy a sense for variety (as well as countless non-metal albums). Consider that variety can be little more than a statistic to some, and wanting variety for the sake of variety is arguably just a meaningless trend. ... "Newness" blurs the lines a little bit because you should consider whether something is actually new or just something recycled and re-packaged. The longer a genre persists, the more it gravitates to the latter and the more the pool of the average grows into an ocean. I personally think the occasional gems and moments of innovation would exist regardless of whether or not the genre itself really persists. In fact, an active desire for any genre's persistence may serve only to hinder the art, particularly art that defies a genre's conditions, instead promoting an ever larger sea of averageness. This loosely relates to the suppression of exploration and art in music and media already in place on a much broader level.
You have to step back and look at
why, specifically, you want it to persist. Not wanting to listen to Judas Priest for 168 hours at a time really isn't the answer.
I can't address metal_xxx's comment briefly, sorry. It's not really a question of right and wrong per se.
And no, Zad, that wasn't my point. However, I can't settle on a good and proper way to explain it right now. ... It's especially difficult because I don't really think a metal band
can make it big right now. But, yes, I do think Metallica
may have had a hand in that...
I hope this post kind of helps, but it probably doesn't.

Traptunderice is sorta on the right track, but not quite. Mainly, I'm not trying to tell you what you should want, I'm just trying to illustrate some of the deeper motivations and ramifications that come with the position of wanting metal to persist.