Lemmy Kilmeister. SXSW, 2008.

Someday, Lemmy will die. Maybe that day will come soon. For the last couple of years, he hasn’t been a well man. He walks with a stick, slurs his speech and his rapier wit seems diminished. He has even made half-hearted attempts to cut back on the booze and cigarettes.

Most shockingly, Lemmy has had to cancel shows; sometimes he can’t even finish them.

This should be no surprise. He will be 70 on December 24th this year. A 70 year old with decades of constant substance abuse and relentless touring shouldn’t expect to live much longer.

But there’s something about the prospect of Lemmy dying that is strangely unnerving. It isn’t just about disappointment at the revelation that he is mortal after all, although, pace Keith Richards, rock and roll certainly celebrates those who seem immortal. Rather, the prospect of Lemmy’s dotage and death reveals the unstable foundations on which today’s rock world rests.

Last June, Motorhead played the UK’s Glastonbury festival for the first time. The band were only the second metal band to have played the festival, following Metallica’s appearance of the year before. Given the prestige of the festival, and the novelty of acts like Motorhead playing it, one would have expected some acknowledgement of the occasion from Lemmy.

Yet in an interview with the BBC before the set (in which he smoked and played a fruit machine), Lemmy was utterly blasé. There would be no concessions to the occasion; as Lemmy explained ‘everyone gets the same set.’ And that’s what happened: from ‘We Are Motorhead’ to ‘Overkill’, the band played their usual set. Or at least it was a usual set from today’s Motorhead, with Lemmy near motionless, his playing barely in time. During “Overkill” he even accidentally sang the words to “Ace of Spades.”

Compare this to Metallica’s appearance at Glastonbury the year before. They were clearly over the moon to be playing. They made a special intro video for the show, Lars Ulrich told everyone who would listen what an honour it was, James Hetfield thanked the crowd with humility and grace, the whole band played with a verve and enthusiasm that as truly touching.

Metallica certainly won the Glastonbury crowd over that night in 2014, but consider this: among hardcore metal fans Metallica is a band that is increasingly a source of derision and exasperation. Their capricious musical experiments and Lars’s impish passion have stretched many fans’ patience to the limit. Contrast this to Motorhead, who are adored for their steadfast predictability. Even if Lemmy is too sick to play a decent set, his reputation does not suffer.

There is something perverse going on here: a band that professes itself to be utterly immune to circumstances and has no desire other than to repeat itself is immune from criticism, a band that is highly sensitive to its audience and is determined to push itself musically is derided.

It’s increasingly clear that rock and metal acts are required to confine their promethean tendencies to their early years. In their first ten or twenty years they can develop and consolidate an audience while continuing to innovate. At some point though, the audience ceases to grow – both in numbers and in terms of musical tastes – and bands are now required to repeat themselves.

Motorhead are masters of this art. They offer a reassuring presence to their audience. Their albums are variations of the ever the same. Even if Lemmy is starting to show the ravages of time, his determination to continue if anything reinforces the comforts of repetition.

We can speculate as to the sociological reasons why rock fans so often cease growing musically after their 30s. There isn’t anything intrinsically wrong with it. Why shouldn’t music turn into a source of familiarity, comfort and nostalgia as one ages? The problem though is that the ability of rock to provide such repetition may be being eroded. And this is why the death of Lemmy is going to matter…

Lemmy and Motorhead are part of a smallish canon of rock acts that have achieved the ability to continue to repeat themselves indefinitely and retain an adoring audience – The Rolling Stones and AC/DC being other examples. The majority of them come from a ‘classic’ period of rock history, their heyday being the 1960s to early 1980s. They remain essential as the polestars around which rock revolves; sources of stability and endurance in the musical firmament.

The problem is that the ability of new acts to gradually join this classic pantheon is much diminished. It’s not that there are no big bands anymore, even if the kinds of revenues bands can expect these days is certainly diminished. But it’s very unclear to me whether today’s top acts – Muse, Foo Fighters, Coldplay and the like – will provide the kind of quasi-mythological weight that can stabilize rock. In a world where music – along with much else – is facing a period of chaotic instability where the old rules no longer seem to apply so much, what can stop rock dissipating slowly, unanchored by its weighty forebears?

Aesthetically, this is something that I cautiously welcome. The death of Lemmy, along with the other big beasts who will follow him in the next couple of decades, will be a sad moment, but hopefully a liberating moment too. Rock without dinosaurs may become fresher, less in debt to the past.

At the same time, something precious will be lost. For decades we have relied on the likes of Lemmy to remind us that some things will remain ageless. Motorhead’s repetitiveness was a heroic fantasy, that we could preserve our youth in amber, that we would always have our Gods.

When Lemmy dies, I will mourn him.