Apple is an iPhone business — and now that business has stalled. That's the message that echoed deafeningly throughout the tech world after Apple CEO Tim Cook took the rare step of issuing a warning regarding the company's upcoming results on lower iPhone sales.

After the announcement, the stock collapsed. People were stunned. What was for some time the world's biggest company suddenly seemed fallible, and there is now a sense that the dearth extends beyond Apple, auguring an upheaval in the current era of tech.

There are many reasons for Apple's drop in sales, but the main one is also the simplest: The smartphone market is mature and there is simply no more room for the kind of rapid growth we've seen in the past decade. Two companies, Apple and Google, appear to have actually bumped up against the limits of capitalism: With smartphone sales plateauing, there is in essence no one new left to sell to.

But mature markets are decidedly not bad or unprofitable. Often, they can usher in a new era. Where we head next in tech will depend on how the sector responds to the change in the tech cycle and what business models emerge. For Apple and its competitors, this is the central question for the next few years.

We often talk about this era as belonging to the smartphone, but the real progenitor for the current system in tech isn't the iPhone — it's the iPod. By matching its hardware to the iTunes music store, it was the iPod that first popularized the idea of a vertically integrated tech ecosystem for consumers. That business model then became the default: The iPhone had the App Store and iMessage, Android had Google Play, PC gaming had Steam, Xbox and Playstation had their own stores, and so on. Hardware became more than a standalone product — it was the entry point into an entire software ecosystem where cultural life was unfolding: If you wanted to know what was happening on newfangled networks like Twitter or Instagram, you more or less had to get a smartphone.

That model also spread to the internet. Facebook structured itself as a walled garden, and the game turned into one of hooking users into a platform and then keeping them there. Apple's iMessage is a great example: The mere fact that it is both easier and better for iPhone users to stick to the default messaging app keeps people coming back.

But the vertically integrated model has its limits, especially in mature markets, because what was once convenient can start to feel restrictive. Apple's stated reasons for its drop include an economic downturn in China, people holding onto devices for longer, and a battery replacement program that delayed some people upgrading. These reasons are undoubtedly true. But they aren't the whole picture.

Chinese consumers tend to be less loyal to Apple because the hooks that work in North America — iMessage et al. — don't have the same pull in China, where mobile systems like WeChat dominate. There isn't the same penalty to switch because WeChat just hops over to another phone. Further, some Chinese brands like Huwaei and Xiaomi are starting to carry cultural cachet there, weakening the iPhone's luxury appeal, especially when Apple continued to push prices up.

Meanwhile, in the rest of the world, Apple's own strategy of making its phones much faster than the competition and keeping them updated for years has ironically backfired, making a 2- or 3-year-old phone fine for most people. Additionally, Cook's suggestion that the battery replacement program — designed to address the controversy over Apple slowing down older phones — was responsible for some lost sales was a startling admission: It meant that planned obsolescence was in fact part of Apple's business model.

Rapid adoption based on the rise of online ecosystems, plus frequent hardware upgrades, were the tenets of a tech era that's now waning in part because Apple became a victim of its own wildly successful business model.

Where does tech head next? Two related things will happen: First, like Microsoft and others before it, Apple will shift its smartphone business from one based on an ever-growing user base to one focused on serving the existing base. That means a much sharper focus on services like Siri and Apple Music, a continued focus on expensive, high-margin devices (don't hold your breath for Apple cutting prices; it's unlikely), and perhaps some kind of subscription hardware program where you pay a fee to always have the latest iPhone.

But on top of all that, there will now be an increasing emphasis on the next tech cycle and the innovations that will spur it. We don't yet know what the next cycle will hold, but I'd expect voice computing, the cloud, and transportation/mobility to be key. Computing will start to become more ubiquitous; instead of being attached to specific devices, it will be something that follows people around. Autonomous cars and even things like electric scooters are all part of this shift. Even environmental and climate challenges may play a role in propelling the next tech cycle forward.

We are at an inflection point between different periods in the evolution of both tech and society. As one era has managed the remarkable feat of pushing the limits of capitalism, what comes next may take the form of something familiar — like shiny new technology that emerges in known historical patterns — or it may shake the ground beneath us.