Take a deep breath, Macaholics. Think different. Apple might be the envy of the technology world right now, yet in its core business of music—iTunes and those beloved iPods—the company is veering toward trouble. Sooner than you think, the iPod as we know it will seem as nutty as a no-down-payment balloon mortgage.

For generations, consumers have wanted to own their music—vinyl, cassettes, CDs, and 99-cent downloads. But today, the economy seems stuck in a death spiral, just in time for a sure-to-be-dismal holiday shopping season, and that malaise will nudge consumers toward a massive shift in mindset. Hauling around thousands of songs on a hand-held device or computer hard drive just so you can listen to your favorites will soon feel overly extravagant and cumbersome, like keeping a cow so you can eat your favorite cheese.

Instead, we'll get music from "the cloud"—technically, "somewhere on the internet, but who cares as long as it shows up when I press this button." We'll have access to a service that holds every song ever recorded, letting us listen to anything, anytime, from any device. Pocket-size gadgets will connect to high-speed cellular, WiFi, and satellites linking to the cloud—to your music—at home, at work, on overseas flights. Want to hear that Bread album you used to have on vinyl? Just tap into the cloud and listen. Maybe you'll pay a subscription fee or maybe you'll put up with ads in order to listen for free. When that happens, Apple's model is toast.

The cloud is already forming. In September, MySpace began offering free, unlimited, ad-supported music. Microsoft's Zune player connects to WiFi, and its $14.99 monthly subscription service allows access to 3 million songs. In Britain this fall, Nokia is testing Comes With Music, a phone-music player offering a free subscription to Nokia's new wireless music service. And next year, Sprint will switch on its Wi-Max system—high-speed wireless internet covering large areas and easily delivering music to gadgets—in a handful of cities.

Fortunately for Apple, these emerging pieces don't work together. On their own, they can't challenge Apple's music hegemony. iPod commands 72 percent of the music-player market; Zune has 2 percent. The most successful music-subscription service, Rhapsody, has never put a dent in iTunes.

But as Intel's Andy Grove likes to say, if technology can make something happen, it will happen. And technology will knit the pieces together. Wireless internet will blanket the earth, and someone will marry that with just the right kind of device and just the right cloud-music service. A true challenger will be born. It might be a startup or an established player like Nokia. "Someone will get this right," says Ali Partovi, C.E.O. of the music-sharing service iLike, but he's not sure Apple can do it: "Apple would be cannibalizing its existing strategy."