Apple VP Greg Joswiak:

“We bring a very homogenous customer base to developers where 90% of [devices] are on the current versions of iOS,” says Joswiak. Apple’s customers embrace those changes and updates quickly, he says, and this allows developers to target new features and the full capabilities of the devices more quickly.

That is such an important point for Apple—its customers update hardware and software quickly, which allows developers to take advantage of new APIs and technologies in their apps. That, in turn, leads to more sales for developers and Apple, all while keeping the customers happy and engaged.