[Edit to replace a broken part of the initial post]

I’d define post-cyberpunk as “building on cyberpunk but not quite within the genre”. So maybe you have a world where technology is ubiquitous and people put cyberware in their bodies but it’s not really a dystopia. Or you do have a dystopia but the story is focused elsewhere.

For instance, The Diamond Age depicts an ultra-globalized world ruled (more or less) by a cabal of corporate entities. But it’s also technically a post-scarcity society and the novel is a coming-of-age story rather than a direct struggle of underdogs against an oppressive system. It’s not really cyberpunk but you can tell that it shares some of its DNA. You could probably tell cyberpunk stories in that world but this isn’t quite one of them.

I’d say that cyberpunk at its core is built around an unjust, corporate-dominated society with pervasive (and often intrusive) technology in which an underdog (or a group thereof) fights to resist the system in some way. If you deviate from that you either have post-cyberpunk (if the work is still relatively close to the themes) or something else with a cyberpunk aesthetic (if the core themes are barely referenced while the aesthetic is maintained).

Like always all distinctions are made up and all lines are blurry. When is something post-cyberpunk and when is it something else with a cyberpunk coat of paint? I can’t give any clear answers here.

For example, would System Shock qualify as cyberpunk, post-cyberpunk, or neither?

The intro and basic premise are very cyberpunk: You are a lone hacker trying to steal the blueprints for a military-grade implant from a corporation. Then they catch you and a corrupt exec gives you a deal at gunpoint to disable his space station’s AI’s pesky ethical subroutines. That all tracks.

Then you wake up, everyone is dead and the rest of the game is a sci-fi horror survival shooter. While corporate mistreatment of people is referenced every once in a while, it’s not really all that important. So I’d say it’s probably not a cyberpunk story. But is it post-cyberpunk as its story springs from a cyberpunk premise? Or is it sci-fi action with a cyberpunk coat of paint? I can’t really decide.

I think of solarpunk as post-cyberpunk because it exists as a response to cyberpunk. But cyberpunk continues, so post- as a “hey it’s done, everything afterwards is something else” declaration doesn’t work for me. You can write and direct a film noir movie outside of the film noir time period. The problem with labels is that different eras are marked by different patterns, but also different years. If something is written using the elements of the 1980s cyberpunk but it’s actually written in 2026, is it classic cyberpunk because of the themes or is it post-cyberpunk only because it was written decades later. The labels become less useful if you bind yourself to odd conclusions based on odd taxonomies.

Cyberpunk means different things to different people, so some might consider it over because the things that defined it for them are done. But honestly it’s even more relevant now because so much of the implied criticism in cyberpunk media in the 1980s has continued and arguably gotten worse with corporate hegemony, authoritarianism, surveillance states, etc.

You best start believing in cyberpunk dystopias, because you’re in one. It just is also sometimes a boring dystopia, but that’s just how reality goes. Fiction is expected to be more believable.

I guess you could call post-collapse stuff like Horizon Zero Dawn post-cyberpunk, but that kind of feels like a cop out

But on your point, I think cyberpunk has, and will continue to evolve as our modern day technology develops. I don’t think that really makes a newer work post-cyberpunk, just different imaginations of a possible future.

Defining cyberpunk, as with any genre, is difficult. Where is the line between sci-fi and cyberpunk? Is 2001: a Space Odyssey or even Metropolis cyberpunk? Maybe, maybe not. Star Trek or Star Wars, probably not (is it the aliens?)? Blade Runner? Almost certainly. But there are commonalities between all of those that are parts of the cyberpunk genre

fwiw I have a cyberpunk-related dissertation laying around that I keep meaning to read, and somewhere towards the intro it says:

In Rewired: The Post-cyberpunk Anthology (2007), James Patrick Kelly and
John Kessel propose a new consideration of what they see as later evolutions of
cyberpunk works and categorise these texts as “post-cyberpunk”.

…

Kelly and Kessel’s argument centres around the loss of cyberpunk’s ‘revolution’.
That once ‘popular culture hacked into it and turned cyberpunk to its own purposes’ 28 it
became ‘tamer’ and ‘fuzzier’ in definition. They see this progression as what allowed
cyberpunk to be contained into a single moment that has long passed, ‘consigned to the
dustbin of literary history.’ 29 Cyberpunk’s initial authors fought for it to be established as
a rebellion against other, as they might have seen them, stagnant or limited SciFi
genres. Yet once it moved away from this cult of personality, it seemed to lose its
power. Kelly and Kessel reinvigorate it through their conception of post-cyberpunk,
describing fresh stories ‘long after classic cyberpunk’ that foster its same ‘obsessions’.
Their work here is fuelled by a positive intent: to acknowledge that cyberpunk concerns
have been maintained in fiction through to the contemporary texts they have chosen for
their connection.

https://etheses.bham.ac.uk/id/eprint/14422/ (pg 7,9)

edit: I mean this as a contribution to your statement “I’m not sure if there’s a work that ushered in this new genre”. Clearly Kelly and Kessel’s proposal isn’t the last word, and the dissertation writer himself has disagreements with it. However, Kelly and Kessel are/were major SF writers so I’m guessing they were an important part of the definition.

Not sure of all the book references, but I think of post-cp as being a few generations later. So imagining cyberpunk being at its peak, and then 50-60 years later, it’s old news with plenty of new problems and advancements.

I think post cyberpunk would be akin to magic, kind of like Warframe.