Earlier quoted context omitted.
They still make money on every single pc/laptop that ships with windows which is still their biggest money maker with office. If they truely open source windows (BSD or else) it will be free to ship for OEM and Microsoft will lose one of their biggest source of income. tl;dr: not gonna happen
Android is open source, and still (nearly) everybody is locked into Google's version with licensing costs. Google open-sourced nearly everything, while managing to make their "apps" so entrenched that every customer expects them and even a lot of apps don't work without them.
Nearly everything about Android the operating system. Android the app platform is deeply tied to Google Play Services, which is not open source and is once more deeply tied to Google's online services.
And they've re-routed apps' access to basic phone data like GPS, camera and microphone through Google Play Services, so that if you want to use any app that uses those services you also have to let Google log those data.
It's almost as bad as tivoization from the FOSS perspective, while also invading your privacy. Yay.