Well the Windows Phone redesign (Windows Phone 7 & 8) was equally significant, if not more so, as a design direction change for Microsoft. And there are certainly similarities between WP7/8 and iOS7.
Android perhaps less significant as that has been a set of gradual changes, but the actual design language in the latest version of Android is starkly different to the first release.
I think the article is referring more to the fact that all the changes shown were done in ~7 months. He's marvelling less at the result, and more at the fact that a huge organization like Apple can seem to pivot so hard and quickly. Thinking about that makes him wonder how, or if, his own team could pull of such a feat... hence it being Rorschach test since it makes you introspective.
Android perhaps less significant as that has been a set of gradual changes, but the actual design language in the latest version of Android is starkly different to the first release.