I always think music is a better model for videogames than film: individual series of games can be thought of as performers, reaching a feverish apex of popularity before settling into comfortable grooves and hoping for the rare, Kylie Minogue-like creative resurgence.

What’s unusual about music is that most of its critical discourse revolves around pop. It’s not because pop music is what’s popular – though that helps – but because pop is obsessed with the new. It’s an eclectic, hybrid genre, grabbing new sounds, new ideas, new fashion from wherever it can, subsuming what it needs and discarding the rest. When pop finishes with an idea, that idea either dies or it calcifies as its own genre and people stop talking about it.

In short, Assassin’s Creed is now the adult contemporary of videogames. Assassin’s Creed: Unity is Michael Bolton.

Here’s the second thing: this is not a criticism. This is how it’s supposed to work.

When Assassin’s Creed first launched, it was thrilling: a historical game set in an open-world city, defined by a novel, free-running movement mechanic, and with stealth based around crowds not shadows. The first game was embryonic, but over the past seven years we’ve watched its ideas develop and its execution improve.

We’ve also watched it calcify. Innovation has became iteration. This is what happens. We helped it grow, we took what we could from each other, and now it’s time to wave it off.

Assassin’s Creed: Unity is set in Paris during the French revolution. It’s stunning to look at: higgledy-piggledy rooftops stretching as far as the eye can see, the streets thick with smoke and dirt. The mission playable behind closed doors at Gamescom this year is a co-op heist set in the tunnels beneath a hospital – #nosewers – and the monetary rewards for your stealing scale dynamically based on how stealthily you complete the mission.

Even with a co-op partner, that mission is a parade of familiar ideas: track one, a reassuring hay bale leap; track three, an aerial takedown; tracks four, five and six are stabbing schlubby guards with wristblades; track seven is a duet with Splinter Cell’s crouch-and-move stealth, track eight is a crowd-pleasing crowd scene; track nine a rooftop escape. A new sense of fashion – you can design your own ensemble – does nothing to obscure that what once was exciting is now comfortable.

Which begs the question, what else would you want from Assassin’s Creed? This is why the series is loved and popular. Some games maintain cultural relevancy through scarcity – Half-Life is David Bowie – and a few through constant Madonna-esque re-invention. Not all games can or should do that. That doesn’t mean you shouldn’t keep making them, either. This isn’t the point at which Assassin’s Creed should stop, but the time in which it should take up its residency in Las Vegas.

It’s not that no one should write about these games, either. They have an audience. Old work should be constantly re-appraised. Sustained popularity is an interesting phenomenon in its own right. Everyone likes When A Man Loves A Woman. Perhaps in a decade or two or four, a remix, genre revival or Tom Jones-like album of duets will see the series relevant again.

But the reason to establish Assassin’s Creed’s fading relevancy now is that the alternative – maintaining these games long-term as part of the central critical discourse – turns every game critic, journalist, blogger and writer into stenographers, tapping out yearly (twice yearly!) patch notes. That’s an essential job, and I’ll be doing it excitedly for the yearly series’ I love for a long time to come, but it shouldn’t be default. Even audience size shouldn’t guarantee it.

When people complain about there being too many sequels, what they’re really saying is that they’re personally bored of something. It doesn’t mean that a company shouldn’t continue to serve the audience they’ve built, and the millions of people who still love it and aren’t bored by it. Instead, we make space for new ideas by not continuing, reflexively, to talk about the old ones. Thanks for everything, Assassin’s Creed. You were useful. What’s next?