Apple just became the first US company to surpass $800 billion in market capitalization. Speculation quickly followed that Apple would soon become the first $1 trillion company, with a rumored $1,000 iPhone 8 coming at year’s end. The company’s share price has been on a tear since the beginning of the year, and sales of the iPhone 7 have been strong in part because of safety issues surrounding rival Samsung devices. Apple retains an enviable brand image and a devoted consumer base.

And yet, the shadow cast by past corporate behemoths is creeping up on Apple. As valuable as Apple is now and could still become, the company looks vulnerable to being eclipsed in the years ahead, if not threatened to its corporate core.

Apple makes hardware. It manufacturers a product. Yes, that oversimplifies the vast network of users connected by its software and bound by iOS. But Apple’s software is hardware dependent; it runs on Apple products. That makes Apple more like the manufacturing giants of the 20th century than like the software and digital players of the 21st. By that standard, even a trillion-dollar vote of confidence now hardly portends business immortality for Apple.

Wait, what? Apple is one of the world’s most dominant brands already, and its user base is expanding. More than 700 million people worldwide use iPhones, not to mention the hundreds of millions more who use Apple computers and tablets. While its global market share is decreasing in face of varied competitors, its overall market is still growing.

But take a look at the list of Fortune 500 companies in 1955 compared to today. As of last year, only 12 percent of the mid-20th century list of the world’s largest companies made it to the second decade of the 21st century. Of the top 20 then and now, General Motors, Exxon, and General Electric remain large and profitable. But US Steel is severely diminished, and Armour (which made packaged meats as well as Dial soap) is no more. It gets worse from there. Chrysler and GM are still major companies, but they have flirted with bankruptcy and liquidation; General Electric and IBM have managed to transform themselves many times over, and they continue to exist today only because they bear scant relation to what they were and what they sold 50 years ago. How Apple will transform itself in the coming years isn’t clear—and the company is doing little to lay out an effective vision of its future.

One lesson here (one that we humans seem to learn and then forget with numbing regularity) is that tenure at the top can be remarkably short-lived. Magazine covers lauding success and power in the present have a way of seeming quaint and dated within a very short timeframe (much as magazine covers themselves are coming to seem quaint and dated!). Size and market share for mega-companies are no guarantee of future size and market share, no matter how potent the franchise or deep-seeming the moat.

Moats and networks are the current buzzwords of tech success. Here Apple looks unassailable now but strangely defenseless going forward. It has a network of apps that work within an Apple ecosystem and users who seem not only content but enthusiastic. Google has certainly built a real rival in its Android platform, but one that works as without generating direct revenue for Google (advertising and app revenue from Android are a different story). Apple for now has a virtuous circle of users who pay for the hardware and then pay for services linked to its software.

Zachary Karabell About Zachary Karabell is an author and head of global strategies an Envestnet; his most recent book is The Leading Indicators: A Short History of the Numbers That Rule Our World

The world, however, is moving quickly toward a digital future where devices become commoditized. It is likely that within a decade, devices become more and more interchangeable, less expensive, more powerful. They will devolve into conduits for various software and digital services that generate the bulk of profits. Already, Apple’s proprietary ecosystem is becoming less closed. A few years ago, if your family (like mine) had iPhones, Macs, and iPads, the pain of switching to Windows or Android platforms was intense. There was little compatibility and porting was a pain. As Apple has become ever larger, it has also bit by bit become more open, as its customers have demanded. More applications and the data they depend on live in the cloud, and more people use a variety of devices to lead their digital lives.

It isn’t at all clear what Apple could do to fortify itself against these trends, or that it could find the motivation to do so. It is an insanely profitable company generating billions in cash every week. Rarely do companies with a franchise that lucrative make radical shifts. Alphabet/Google is determined to find its next multi-billion dollar revenue stream to lessen its dependency on search; Microsoft has been doing the same with its reliance of Windows. Neither has yet to find that next unicorn, but they have the advantage of being firmly housed in the digital world and not, like Apple, tethered to making devices that are rapidly becoming generic.

No Secrets

The companies that have survived the decades have either become shadows of their former selves—think US auto makers—or different companies entirely. IBM managed to shift from a maker of high-tech 20th century machines (typewriters and computers) to a seller of high-tech services and solutions, but it still had a machine franchise. It too is now struggling to find a next wave. GE has spun through multiple iterations, and while it isn’t in any danger of going out of business, it is finding global competition and margins an ongoing struggle. What is Apple’s long-term plan for itself in a world that is definitively not moving in the direction of its model?

To be clear, I happen to own Apple stock personally; it’s been a very good investment, and one that I continue to hold. Why? Because in the next few years, it seems more likely that Apple will reach that trillion-dollar mark than flounder. The next wave of dramatic changes in how we use hardware to access software is not yet on the visible horizon, and it may be that Apple has a dramatic plan to position itself accordingly when that comes nearer. For the near future, Apple is likely to grow and stay dominant, just as Nokia did throughout the 1990s and into the early years of this century.

The Nokia example should not comfort. At its peak in 2007, Nokia had 41 percent of the wireless handset market. Less than a decade later, Microsoft bought Nokia’s handset line for a scant $7 billion and wrote the whole sale off as a loss not much later. Blackberry, which today has exactly 0 percent market share, peaked at 20 percent in 2009. Apple has less than that now, which means it certainly has room to run. Apple also has a far more robust ecosystem than either of those two ever did. But there is a final challenge for Apple: its culture of secrecy.

Tech innovation over the past few decades has in part been about the products, but also about who gets to tell the story of the future. Steve Jobs was uniquely able to weave a story of the future that revolved around Apple products, and that was part of the alchemy that made Apple an integral part of the world we inhabit now. Yet he also wanted complete control of the narrative, which meant Apple spoke with one voice (his) and then only rarely.

Today, Apple is run by unquestionably competent executives. It does not, however, spin a vision of the future with Apple at the center of a new, evolving ecosystem. Yes, it is spending billions on R&D to design new products and services, but it does not offer a map of what it sees in the world ahead, largely out of fear that doing so would tip its hand to competitors. It prefers to unveil its map when it is rolling out products that utilize it, not before, and not after. Apple under its CEO Tim Cook alludes to a future of community and AI, as does every single major and minor player in Silicon Valley. That is less a map than a sensibility widely shared.

No matter what the future holds, Apple has been one of the world’s most important agents of change. The personal computer enabled the first wave of the 1990s tech revolution, and the iPhone triggered the next phase. The smartphone is a platform that has opened the digital world, and Apple will forever be linked to that evolution. But that does not mean that Apple will have anywhere near that position decades from now—or even a decade from now. To believe that Apple will dominate the landscape for years to come, simply because of where it is today is to ignore how quickly things can change, how ephemeral power and dominance can be, and how thoroughly unpredictable the future is and always has been.