I wish this to be the definitive statement on this opposition.
Like the Renaissance as compared with the Enlightenment, here the question will be, who betrayed what? when? and when may we say that the character of the epoch was completely undermined or reversed?
A Brief History
Black metal and death metal, although no one knows it, "died" at the same time (in terms of the most famous bands, in America, retrospectively). The ends of both genres coincide; do their beginnings?
The first Death Metal bands of any importance are Death and Morbid Angel. [Obscurity counts for nothing in this argument.] The first Black Metal bands of note are Bathory and Celtic Frost. Thus, put crudely, Death Metal is originally an American genre, and Black Metal a European one. [Exceptions can be found even in this early history.]
However, both Bathory and Celtic Frost developed away from their early, raw aesthetic towards more pretentious and complicated art-metal: Bathory with 20-minute ballads about viking conquests, and Celtic Frost with violin-accompaniments of Baudelaire's poetry. (no shit) Thus, Black Metal was immediately moved away-from by its inventors. The early aesthetic was developed, more or less simultaneously, by more extreme groups such as Beherit, Sarcafago, Blasphemy, Mayhem, and Von. The most famous "intervention" in Black Metal, though, was by the Norwegian Death Metal band, Darkthrone. Jettisoning members who wanted to play the technical Death Metal of their first album, Soulside Journey, Darkthrone decidedly rejected all their talent and instead meticulously "played dumb," aiming for the sounds of early Bathory and Celtic Frost. Thus, the real invention of modern Black Metal already consists of a re-opening of a formative aesthetic moment.
The single albums which, from my viewpoint, announce the death of these genres are, Slaughter of the Soul (1995) by At the Gates, a melodic pop-punk record masquerading as Death Metal, and Panzerfaust (also 1995) by Darkthrone, the first definitive retreat of this band to "merely" playing Celtic Frost riffs. Both these death knells have been springboards for hundreds of crap bands who did not "get" it.
The Definitive Statement on the Question
Undoubtedly Darkthrone were correct in abandoning Death Metal in 1991. Just as certain is the genius of Darkthrone's later career, which approaches a hardcore punk sound and is less and less "serious." It is supremely important that Darkthrone have always been 1) ironic, despite their extreme dedication, and 2) regressive.
There are several epochal developments in rock music: Bob Dylan going electric, Sergeant Pepper, The Stooges' Fun House, Kraut Rock, and the consolidation of Punk by the Ramones. In punk, the decisive trinity is The Ramones, Black Flag, and Discharge. In Black Metal, Celtic Frost and Bathory (I believe that Bathory "contains" Venom) are IT. Within this binary is everything necessary for the sound. But the genre has been completely taken over by adjectives, rather than influence. Rather than the incredible, unfathomable development at the core of the sound, the invention of Black Metal has been rendered a mere aesthetic, a production trick, turning Bathory's sound, which was a very close thing indeed, into a "given." What is necessary is to THINK the bizarre, extreme, tasteless, uncompromising, excrescent, juvenile extremism of Hellhammer, Celtic Frost, and Bathory, not to take these sounds as "early" or "undeveloped" or "primitive" in the teleological sense.
What then, of Death Metal?
When I was younger, Death Metal struck me as the last refuge of D&D-playing virgins, who practiced their instruments as a form of masturbation, perfecting a style that was "needlessly technical," and ultimately just playing for other techies. I'm not sure that that is entirely wrong. But now I see it as the most straightforward honesty. The premise is, "Do you like our riffs? Was that solo perfect enough? Could this have been heavier or more interesting somehow?" THE IDEA IS PERFECTION, even quantifiable perfection. That may be dumb, but it is a meritocracy. The best bands are the most well-regarded. Respect is key. The whole thing is very "male" and analytical. That is, extremely unironic.
I said earlier that I much admired Darkthrone's irony. I see this as a very strategic, "theatrical" mode which they pioneered. Members of Darkthrone never killed anyone, burned churches, were "truly" racists, or shot themselves. My favorite anecdote about Norwegian Black Metal is where an interviewer reminds a Black Metaller that Venom were largely joking, to which the metaller responds, "In Norway, we choose to think otherwise." This is irony. But "taking something seriously that should not be" is a matter of positioning, if one is smart enough, and of "sincerity," if one is stupid. Obviously Burzum and Darkthrone fall in the former camp, and Mayhem in the latter.
Why can one NOT "choose to think otherwise" about Venom in after 1995? For one, the genius of Darkthrone, by getting there first, made evident the gap between the second wave of Black Metal, and its mythical origins. By taking the irony SO FAR, the game was "up"; the mock-seriousness exposed its target too much. And so Darkthrone, having achieved all they could, began their long retreat. And Mayhem self-destructed. Burzum went to jail. Emperor drastically changed their sound in a more "prog" direction. Immortal took on a huge Morbid Angel influence. Graveland began to explore the later meanderings of Bathory. Ulver, never a raw band, hardly a metal band, released the ultimate ironic Black Metal record, the supreme Nattens Madrigal, a completely technical achievement of the lowest-fi possible sound. "Symphonic" Black Metal became very popular. etc. etc.
Fast forward twelve years. Black Metal in America has fallen in with the "noise" scene, the ultimate in baseless pretension and image-jocking. Death Metal is absolutely dead. If you see here that I am only repeating the RUSH v. SONIC YOUTH debate printed below, you are correct. Here, Rush are Death Metal, embarrassingly outdated, and Sonic Youth are the endless pretension of post-1995 Black Metal: its limited releases, its "mystery," its redundantly "shocking" aesthetic, its disingenuousness.
Death Metal has no interesting history. Nowadays Black Metal, however, in its haste, neglects everything but the most sensational, misleading aspects of its origins.
*[When I say irony, I mean it in the most exact way, not in the loose sense of today's youths and nervous self-doubters.]