Apple is a fantastic hardware company. And when the rumored iWatch (probably) arrives, it will no doubt be a thing of beauty. But there’s good reason to think that the key to a successful smartwatch won’t be its hardware, but its operating system.

Apple’s genius is in creating personal computing devices that invite us to linger over them and inspire developers to create the best possible apps. But that beautiful hardware may not be enough to compete with the simplicity and the ability to harness huge amounts of data that are built into Google’s smartwatch operating system, Android Wear. Google’s OS, which it released on demos this week, will run on a variety of watches from manufacturers including Asus, HTC, LG, Samsung, Intel, Qualcomm, Motorola and Fossil Group.

Smartwatches are, in some ways, a much tougher design problem than smartphones or PCs. (Witness the failures of Samsung’s and Sony’s smartwatches.) Their tiny screens make it hard to direct their actions—to tap out an email, go to a web page, find a favorite song. So Google has reasoned that it should work the other way around. A smartwatch should have almost no interface at all. It should know where you are and what you want before you do. And that makes it the perfect fit for one of Google’s most innovative and rapidly improving bits of software, Google Now, which is part of Android.

Knowing your needs better than you do is something Google has been working on for a long time. The umbrella term for it is predictive search. Here’s a simple example: Most of us probably pop open a weather app at some point in our morning routine. Given how predictable this is, why should our devices wait for us to signal to them that we want to know the weather? Why not just tell us?

That’s what Google Now is all about. Instead of giving you information through apps or a web browser, Google Now shows you a bunch of virtual cards that already have the information you (probably) need at that moment. Just swipe a card away to get to the next one. You can see it in action in Google’s demo of Android Wear.

Why Apple lacks a Google Now competitor

Apple has plenty of talented software engineers, but the company’s real strength lies in hardware, and the operating systems that run on it. Its internet-based software services—iTunes, Siri, Apple Maps—are narrow in scope compared to Google’s services, which have come to dominate so many people’s online lives.

It’s Google’s pervasiveness that’s key to making Google Now—and by extension Android Wear and all the Google-powered smartwatches—usable. Google needs to know as much as possible about you—your calendar, the contents of your emails, the identities of your contacts, where you go in real life and online, and what you look at, click on or buy when you do. The more Google knows about you, the better it can predict what you might want to do or know about next. And having an always-on companion like an Android-powered smartwatch can only make Google’s knowledge of the people it makes money from through advertising that much more complete.

A lot of this information is on the iPhone too, of course, but Apple has so far shown almost no desire to mine this data as Google does. What’s more, the ubiquity of Google’s services means many people aren’t even using Apple’s default apps anymore, and are instead going straight to Google’s apps and web services—like the (excellent) Gmail app for iOS, which many prefer to accessing Gmail through Apple’s native email app.

Aside from the fact that many of Apple’s services lack a web-based component that makes them accessible on any device, it’s not clear Apple even has the expertise to crunch all this data in the way that Google Now does—or to use that data to predict our needs. Apple had a chance to create something like Google Now in 2010 when it acquired the voice-powered personal assistant Siri, which has its origins in research conduted for the US military. One of the intentions of early versions of Siri was “context awareness,” precisely the thing at which Google Now excels.

Even if Siri were revamped now, however, it’s not clear whether Apple knows enough about its users to provide them a Google Now-like experience. Predicting what people will do next is precisely the kind of big data problem where more information is always better. Apple could try to catch up in this area, but Google has a tremendous head start.

Apple can always chart its own path

Even without Google’s predictive search capabilities, it’s certainly possible that Apple has thought of a different way to solve the design problem of what a smartwatch is for. Apple is a hard company to bet against precisely because it raises the bar for itself again and again.

For example, smartwatches might ultimately turn out to be more like smartphones than Google’s Android Wear suggests. Plenty of startups are betting on this, and have already come up with ways for people to write emails and consume huge volumes of text on even the tiniest of screens.

Plus, there’s Apple’s enormous clout with developers, and its marketing prowess. If Apple can create an iWatch that people want to buy because it’s beautiful and cool, developers might just figure out how to make it every bit as useful as the devices powered by Google’s software.