I think they qualify. They're not at the same level of popularity as the more widely acknowledged institutions [Iron Maiden, Judas Priest, Slayer, Metallica, Megadeth, Manowar] but they certainly possess the requisite qualities.

Been around for 25 years

Survived a bevy of lineup changes without ever having broken up

Continued releasing albums at a relatively steady rate despite this

Have a very dedicated group of core fans that will continue to listen to them and purchase their new albums no matter what their recent track record has been. And despite the fact that they're about 2 decades removed from a 3-4 album span that's considered their 'golden era'.

Frankly, I have a hard time understanding how they never managed to catch on in the mainstream.

They came too late. Mainstream metal media hacks like Eddie Trunk have a hard time believing that any band that debut as late as '86 is musically relevant or influential.

I... don't know who Eddie Trunk is...

http://www.eddietrunk.com/

A metal aficionado with a weight problem; who believes that Priest weren't any good until British Steel.

...and people pay attention to what he says?

He's that guy from That Metal Show on VH1 Classic, and does some heavy metal/hard rock radio shows.

I've only seen one episode of the show, but I give the guy credit for defending Reign In Blood against Vulgar Display of Power as the "meaner" album. Everyone else on the show, including the other hosts, the audience, and two guys from Extreme (the hard rock band, not the death metal one) who had "never heard Slayer" voted for VDoP. Fucking awful show.

Edit: forgot the "voted for VDoP" part. Pretty silly sentence fragment without it, I guess.

The other hosts are idiots who obviously aren't knowledgable at all in the genre and are just there for the comic relief.

I agree with OP more or less. Candlemass are a good example of a long standing, classic band that is incredibly consistent and never to be doubted of their ability to continually make good music without ever once comprimising thier sound.

I don't think they ever caught on in the mainstream as they lack the melodic or fun-bang-your-head-type element in their sound in comparison to the other bands mentioned in the OP.

Yes, doom metal is a lot harder to digest than maybe Maiden or Priest for a newbie to metal or the mainstream..

Especially in the case of Messiah's vocals. I tend to look at it the same way as, say, King Diamond, they will polarize people, you will either love them or hate them.

Their music is also quite oppressive most of the time as well, allowing only fragments of light and hope to punctuate through. Prime example of what to look forward to with a Candlemass album is the Nightfall cover painting. A thin sliver of light in the sky about to be swallowed by an all consuming Darkness. The juxtaposition of the angel either leaving or leading the old man is proof of that. Small mercies of hope constantly being pursued by darkness/misery etc......which is just fine by me.

Well, they did pretty much disband a couple of times. They just never officially announced it. First after Sjunger Sigge Fürst when Edling moved to do Abstrakt Algebra. He only came back to Candlemass because the labels were interested in publishing his material under that moniker instead of the unknown and unwieldy Abstrakt Algebra. The second time is after From the 13th Sun though I guess it's rather debatable at that point. He did move on to do Krux in the meantime between that album and the reunion of classic Candlemass line-up.

Relatively steady is of course a relative term, but an album per year and then six years of downtime with no real releases is not really steady. There's another gap of six or so years between From the 13th Sun and the reunion. They've got their stuff in gear now though.

But do you really see this kind of material breaking into the mainstream? I mean, there's the slow tempo, Messiah's melodramatic vocals, the dreary and oppressing atmosphere. Definitely not, I'd say. The more recent stuff with Lowe is another matter.

Candlemass, with Messiah, and the first album, rule.

Nightfall Ancient and Tales are astonishing. period.

Yet they are still playing clubs that Metallica and Megadeth became too big for over 20 years ago. However, in 1000 years when Aliens from the planet Metal unearth our bodies and albums, they will determine that EDM is far superior to anything Metallica, Megadeth, or Manowar ever produced.

VH1 also labels Slayer as death metal. Mainstream media input means nothing to pretty much any dedicated metal lover, mainstream media will throw the label "heavy metal" on glam and rock bands, and it has been long established in metal that the music as a whole is certainly not about catering to the mainstream.

Different people have different criteria for what bands are considered as institutions, and to each his own, but there are some that are widely respected. Nearly every metalhead respects Judas Priest and Slayer, two long established and influential bands that never clearly "sold out" (see: Metallica). Other bands like Megadeth and Iron Maiden have stayed around despite much less popularity and making some albums that weren't received as well. Some bands are very widely respected by metalheads, liking them or not, for their importance, such as Death (no longer around of course).

There is no lone survivor of metal standing after decades, there are bands that have been around forever, each of them with something that some people will hold against them (never "big" enough, sold out, made bad albums). Most importantly, "mainstream" commentary on metal is worthless to any dedicated metalhead.

That's true. Especially considering that their S/T released a couple years ago was astounding... I personally think was their best album. And I can't say I've ever said that about an album released in the 2000s about any band that's as old they are.

Though too bad they lost Messiah. I don't like either of the two new albums without him.

The new one might be even better... I haven't decided yet, but the very fact that I'm considering it [which would mean it's their best since Nightfall] is pretty astounding, all things considered.

Fantastic band, and indeed a great example of consistent, solid music over the years.

I really hope I get the pleasure of seeing this band on of these days.

To me, the fact that their best album was their eighth album, released nineteen years after their debut, will always remain as a testament to their greatness.

And Death Magic Doom is fantastic.

The vocalists is most definately the reason why they never broke through to the mainsteam, their music brings on the headbanging joy easily as well as the other bands mentioned, hell, better than. Delightfully heavy band. If they had have someone who sounds like Lowe does now back in the 80's they would have been freaking huge.

King of the grey Islands was better than DMD.