Certainly Apple could do it by flipping iTunes into a subscription service that plays over wireless networks on iPhones. "I don't see anyone really making subscription a blowout success for portables until Apple gets into it," says John MacFarlane, C.E.O. of Sonos, maker of a high-end digital home stereo that taps into cloud music. Apple hasn't hinted at any such plan, though.

Anyway, the more a company succeeds with one business model, the harder it is to, well, think different. (See newspapers, travel agencies, I.B.M. in the 1980s, Microsoft today.) At the same time, whenever anyone leads the tech market, rivals swarm to out-invent and out-innovate. That's why tech superstars inevitably fall. Remember when AOL was king of the internet?

Apple introduced iPod and iTunes in late October 2001. In tech years, they're older than Henry Kissinger. But while its products have evolved, Apple shows no signs of embracing the cloud model. In September, Apple's "major" iPod announcement turned out to be iPods in new colors, plus an iTunes function, Genius, that finds music you might like—just as several websites already do.

"What Apple does best is make beautiful hardware," says Dalton Caldwell, C.E.O. of internet music service Imeem. "If we live in this universe where hardware matters less, Apple will be in a poor position in the market."

As for personally owning music—still not sure you'll give that up? Just think of what you go through to do that. We find, buy, and download files. We wind up with a jumble of thousands of songs; some play on some devices, some on others. If you lose your iPod, you have to reload another. If your hard drive crashes, you're hosed. And you probably bought a whole lot of songs, like Toto's "Georgy Porgy," that once seemed like a good idea but that you now never want to hear again.

Someday soon, cloud music will make you wonder why you ever put up with digital downloads. Then the question is whether you'll be tapping the world's music through Apple—or if the iPod becomes as quaint as a wooden tennis racket.