I wanted to get this thought out about 2 months ago, but here it is now. Better late than never.

There's been a lot of talk around the interwebz about Apple knocking off Microsoft, Google, or __________ (fill in the blank) with the latest refresh of iOS. While it's easy to complain about how this or that already existed elsewhere, rather than pointing fingers and chalking everything up to someone copying someone else, to me the much more logical explanation is that Apple has simply updated its design to be more modern (as have others). To say that flat buttons belong to Android is somewhat naive, because certainly Windows Phone has been leading the way in flat UI when it comes to smartphone OSes over the last few years. Further, if you read into iOS 7 and get your hands on it you'll see that Apple did not simply flatten everything out.

In the developer keynote, Craig Federighi stated that the goals of iOS 7 included three overarching themes.

Deference - The UI defers to the content. It's helpful and intuitive, but unassuming and out of the way. This is a big change from the skeuomorphic ways of the past.
Clarity - Clean, precise UI as well as a major increase in accessibility support.
Depth - This is where Apple has struck gold IMO. They were able to modernize the interface, yet kept a distinctly unique experience by focusing on depth and contextual awareness using blurs and realistic, physics-based animations.

The focus on these themes and the amount of detail included at each and every level of iOS 7 make it apparent how truly unique Apple's approach to a 2013 mobile OS is. And the best part, Apple didn't go sell their soul to the flat UI gods - it's still very much iOS. More at Designing for iOS 7.

No, Apple did not copy Android. Apple took their time in moving on from the iOS design of the old, but they did it in their own way. And if you look at it, all major platforms and companies have moved to simpler, cleaner UI over the past 2-3 years. It's not one company stealing another's idea, it's the major players realizing the direction of design trends and incorporating them how they see fit.

It took Apple two years longer than it should have in my opinion, but as usual they came through with a excellent product in iOS 7 and I highly recommend updating if you haven't already.