Here’s an ending nobody writes a film about. The curves flatten. The capability that seemed to be arriving next year keeps being next year, the money gets bored, the field fragments into a hundred useful specialisms, and in 2050 people talk about all this the way we talk about the promises made for nuclear power in 1955.

It’s worth taking seriously because it’s the historically normal outcome. Almost every technology that was going to change everything changed some things and then settled into being a tool. The pattern is consistent enough to be embarrassing: an early period of astonishing progress that everyone extrapolates, a plateau that arrives without announcement, and a long productive maturity that looks nothing like the forecasts. Anyone who lived through the excitement about a previous general purpose technology has watched this happen at least once, and the people who called the plateau were mocked for years before being right.

A doubt post a few weeks ago made the technical case for the ceiling, so I won’t repeat it. Today’s question is different and more useful: suppose it happens. What does that world look like, and what should we do with it?

The first thing to notice is that fizzle does not mean nothing. It means these systems stop getting dramatically better and stay roughly where they are, which is already enough to reshape a great deal. In the fizzle world, capable-but-not-superhuman systems become cheap, ubiquitous, and open. Every organization has them, every government has them, and so does every criminal, every propagandist, and every person with a grudge and a laptop. That world has real problems, and they are the problems of proliferation rather than the problems of ascent: floods of convincing fabrication, automated fraud at scale, surveillance affordable enough for small actors, and a labor disruption that is smaller than the one this series has described but is still the biggest in living memory.

So the fizzle isn’t safety. It’s a change of subject, from control to abuse, and abuse is the kind of problem we actually know how to work on. That’s the good news buried in it.

The second thing is that a reprieve has a use, and this is the whole reason I’m giving the scenario a post rather than a paragraph. Everything Act 1 said was needed and missing, external testing, liability, transparency, an off switch, becomes buildable in the fizzle world, because the pressure that makes those things politically impossible right now is exactly the pressure of a race that feels close to decisive. Take away the urgency and you get the one thing this situation has never had, which is time. Institutions built during a plateau are the ones that would still be standing if the curve resumed, and curves do resume. There were two winters in this field before, and both ended.

Which is why I’d be careful about how much comfort to take from this ending. A reprieve is not a rescue, and our record with reprieves is poor. The predictable thing that happens after a threat fails to arrive is not preparation. It’s the conclusion that the threat was never real, followed by the dismantling of whatever preparation had been started, followed by the same argument again from a worse position when the next wave comes. If the fizzle happens, the people who spent this decade warning will be discredited, and the discrediting will be thorough, and it will be used for a long time.

I’ll say plainly where I put this one. It’s the second most likely ending on my list, behind the comfortable one, and higher than most people who write about this subject would place it. I hold it at somewhere around one in four, which is not a calculation and I promised not to pretend otherwise. Holding it that high is also what stops the rest of this series from being a religion: if I couldn’t tell you a story where I’m wrong and nothing much happens, you’d be right to discount everything else.

Tonight’s exercise, and it’s the constructive one of this fortnight. Assume the fizzle. Assume you have fifteen quiet years and no crisis to point at, which means no urgency, no funding, and no public attention. Now name the one thing you’d want built in that window, and be specific: a law, an institution, a standard, a profession that doesn’t exist yet. Then ask why it isn’t being built now, and notice that the answer is almost never that it’s hard. It’s that nobody has a reason this quarter.