John Gruber deconstructs Tim Cook’s “revising our guidance” announcement that is shaking the markets today (here’s a link if you want to check Apple’s current stock price, or just type AAPL into Google).

iPhone sales have effectively peaked for two reasons. First, Apple ran out of new markets to conquer years ago. The iPhone is effectively available worldwide.

And:

But there’s a limit on the number of people in the world who (a) want an iPhone and (b) can afford one, and the iPhone reached that 3-4 years ago. A bad economy in China significantly shrinks the number of people worldwide who can afford one. They’re much in the position Microsoft got to with Windows and PCs — they’re no longer an upstart growth company and are now a massively profitable blue chip.

Apple is making that shift from dependence on iPhone growth to services growth. The good news is that Apple’s services are, indeed, booming. This bad news is a bitter pill, but Apple will certainly get past this.

In an interview with CNBC yesterday (I’ll post that next), Tim highlights a number of services growth stories, including record numbers for Apple’s Chinese App Store.

That said, Apple’s services growth is dependent on ecosystem lock-in. That’s good business for Apple, but is it the best experience for consumers? Does that lock-in mean our photos, music, and message threads are captives of Apple’s iCloud subscription?

Gruber’s take is a fascinating read. And don’t miss his look back at Steve Jobs and Apple’s Last Previous Earnings Warning.