There are two axis for fragmentation.
The graph is showing the one that doesn't matter, since you can always target a subset of the APi which is supported by all the versions of the OS; that's the same for both iOS and Android, and it's just common sense code portability. The first product I worked on out of college was TERM software for a small company called Century Software in Salt Lake City, Utah, At one point, we had greater market penetration for async communications software on UNIX systems than UUCP, and UNIX systems came with UUCP for free. We also ran on VMS, BTOS, CP/M, MP/M, Mac OS, and half a dozen other non-UNIX platforms, as well as the 140+ UNIX platforms we ran on.
The secret to this success was to have as small a porting surface as possible, and that's eminently possible with both iOS and Android, although that type of design and coding tends to not be taught in colleges and universities these days, it's still eminently possible. It's just a matter of API contracts.
The other axis is hardware differences, and you can't ignore those for either iOS or Android. Those are the ones you can't get around with API contracts, because they touch on different device capabilities - the most important of which is screen aspect ratio, and that's the very thing that iPhone 5 broke, and it's the very thing the original iPad broke. Sure, there are other important parts to this; there the "I" in "I/O" as well, in particular, of all the sensors, there's keyboard inputs, but for the most part, that has fallen out to touch interfaces, which pretty much everyone other than Blackberry has agreed upon, and GPS. All the other sensors are much less useful to most apps.
If you talk to a Rovio engineer (and I have) on this issue, they effectively target a dozen iOS hardware platforms: to get the best user experience, and to get where they are today, with "Angry Birds" being the top selling mobile game of all time, they've had to adjust to aspect ration, resolution, and OS version. Being a game has meant having a much larger porting surface, in terms of OS interaction. And yeah, this means several dozen Android platforms, as well as their other platforms, but the difference between a dozen and several dozen isn't as large as the difference between 1 and a dozen.
Rather than pointing to Apple infographics, you'd be much better off pointing at the biggest success story in the industry, and doing as they do, rather than doing as Apple would have you do, since it's more important to be a top seller than it is to be portable, if the end goal is popularity with users and income.