Edit: this place should not be named "hacker News"
What are you trying to say? You could make the same argument for any piece of software in existence.
You don't write your program against Linux/unix API, you write it against Android. If Google was to replace Linux kernel in Android with, say, Windows CE kernel, virtually nobody would notice, including most of the Android programmers.
"GNU/Linux took over server and mobile. Nothing stops it to happen in desktop anytime soon."
Going off of first order logic, this is literally the textbook definition of flawed reasoning (at least without some compelling evidence that A implies B).