Marco Arment comments on Google I/O focussing on design.

A software platform’s UI and design ethos can’t be changed on a whim by conference sessions and a marketing push. It’s deeply ingrained, built over the platform’s entire lifespan, and very slow to change. Android’s best apps usually aren’t as good as iOS’ best apps because people who value and demand the best apps — both customers and developers — overwhelmingly choose iOS.

You can’t just decide overnight that you want to suddenly improve an OS design. It is akin to a photographer deciding to take better photos and suddenly his photos improve. It just doesn’t work that way. You need to work on your own artistic taste and photographic vision. That takes time and looking at thousands of photos. And you need to spend hours shooting to slowly discover your personal style.

The platform sets the standard for the apps. Developers and designers take cues from the platform, striving to fit in even when pushing the limits. iOS’ design is clear, high-quality, strongly opinionated, and consistent. It inherently expects quality. There are tons of shitty apps, too, but developers who care about good design are given a strong foundation to build upon and strong environmental norms for inspiration.

The importance of such a strong foundation is clearly demonstrated in iOS’ shift in design for iOS 7. You just need to look at the way app designs, and in many cases the websites of these apps, changed after iOS 7 was released.