“A huge number of people just bought their next iPhone,” he says. “It’s like they went to Costco and stocked up on a shitload of toilet paper.”

In retailing terms, U.S. iPhone buyers “filled the pantry” last quarter, and it’s going to be a long time before they come back for more.

How long? Levin doesn’t hazard a guess, but he points to several factors that would tend to slow down the replacement cycle.

• 72% of iPhone owners have a relatively new phone — less than a year and a half old
• 86% of the people who activated iPhones last quarter were repeat customers. (Android repeats, at 72%, were close behind)
• 30% of those phones were financed, not subsidized

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“Apple’s ability to pick off first time buyers or persuade Android owners to switch has diminished greatly,” says Levin. “Loyalty has increased dramatically.”

And the growing popularity of financing — buying phones over time, like a car — could make it harder to sell anybody a new phone.

“When you are done paying for your car,” says Levin, “you get this sort of ‘ahhh’ feeling, where you can wait for a while before you start buying a new one.”

It’s the same with phones. “When people finally own their phone they may say to themselves, ‘hey I’ve got this phone and its kind of new so I don’t have pay for another one anymore.'”

The two-year subsidy model never made much sense, says Levin, and now it’s going away.

This affects Apple more than Android because Apple’s phones tend to last longer and their customers are more loyal.

Levin, like a lot of analysts, is looking ahead to the next generation of iPhones and wondering how Apple can keep it up.

“For Apple to sell a lot of phones in a year or two,” he says,” they’re going to have to come up with some unbelievable innovation.”

Follow Philip Elmer-DeWitt on Twitter at @philiped. Read his Apple AAPL coverage at fortune.com/ped or subscribe via his RSS feed.