Right place, right time, thanks to carrier subsidies:

For Apple, the iPhone has been a magic money machine. Thanks to carrier subsidies in most developed countries, consumers pay an affordable $200 for the phone when they sign up for a two-year contract. Apple, however, collects $650, with carriers covering the other $450. This is perfect for Apple. It gets mass-market pricing and premium pricing. Plus, its customers come back every two years to get a new phone. And, thanks to Apple's manufacturing efficiency, the company's profit margin on the phone sales is extraordinary.

This magic money machine led to Apple's sales exploding from $37.5 billion in 2008 to $156.5 billion in 2012. That insane sales growth led to Apple's insane stock growth.

But, Apple's money machine has largely run through its opportunity.

In the last couple of years, as the explosive growth in the smartphone market has shifted to lower-priced phones in emerging markets, Apple's iPhone has been smoked by Android in market share. Globally Android has 75% of the market, according to Gartner. In the U.S., Apple has about 50% of the market, according to Kantar.

The iPhone is still a great product, but Apple's advantages over Android seem to be shrinking. If Google can get its act together enough to get its various services (G+, Wallet, Play) to work nicely together (at least on mobile) then Apple will lose one of its last great advantages.

Google has the resources and the potential to make some great mobile services that would rival Apple, but they just can't get their various systems unified enough to create a suite that can play in Apple's league. Part of the reason I never really got into G+ or Groups was that my corporate gmail account blocked me from being able to access those services in my main browser. That would never happen with Apple products.