Because the battle with Android is going to have the same result as Windows vs. Mac did back in the 90s. If you look at the market share numbers, it's clearly trending in that direction. Apple is, of course, desperate to stop this by any means necessary, and that includes litigation.
In 1988 they filled a lawsuit against Microsoft and HP, alleging that Windows and HP's NewWave violated Apple's copyrights in Macintosh's user interface. They cited things like the use of resizable/overlapping windows in Windows and the whole thing was about "look & feel".
The parallels with Windows and the Mac don't stand up.
Standards, largely around the internet, mean that there is no real drive for there to be a single winner the way there was on the desktop at that time.
I have an iPhone, you have an Android phone and we can both text each other, mail each other, tweet each other, share photos, contact each other via Facebook, share links and documents, IM and the rest.
That wasn't true back in the days of Windows vs. the Mac and that was why Windows won out - if you were in the minority camp back then you were genuinely being excluded.
But now users can work together regardless of platform, Apple make money, Samsung make money, Google make money. There really is no drive towards a single platform. Sure those companies all want market share but there's no reason to believe that it has to end up with a single dominant MS-style player.
And in terms of market share numbers it's not clearly trending in that direction. Until very recently both iOS and Android were gaining market share (squeezing Windows Mobile and BlackBerry). Google has a larger market share yes but it's not winning at the expense of Apple, they're both winning at the expense of others and grabbing more of the first time smartphone customers.
As regards the most recent market share figures [1], if anything the momentum is moving away from Android. Android market share actually dropped while iOS continues to grow.
It's still around 50% and I don't think anyone is suggesting it's in any sort of trouble (Horace's headline is a little mischievous), but the narrative that you're suggesting isn't really supported by what's happening.
What really looks like it's happening is a market dominated by two players with everyone else fighting for scraps.
As they are so dependent on Samsung as a supplier I can't help thinking they're trying to get leverage for negotiations of future components, rather than actually kill the Galaxy
It's a mutually dependent relationship. Apple are Samsung's largest customer, Samsung may compete with Apple but they need Apple as much as Apple need them.
To understand how important Apple is to Samsung, Apple have just started buying RAM from someone else (in addition to Samsung). In response the value of Samsung dropped $10bn.
Because the battle with Android is going to have the same result as Windows vs. Mac did back in the 90s. If you look at the market share numbers, it's clearly trending in that direction. Apple is, of course, desperate to stop this by any means necessary, and that includes litigation.