Very much not true. Accounts from the development team call the dev process “fork and run;” meaning, they made a fork of the operating system. Yes, it diverged over time, but part of the reason that a Windows port of an Xbox game is so much easier is that they’re fundamentally the same OS.

And Android is Linux under the hood. They’ve committed code back to the Linux branch and maintained alignment with the LTS kernel since the start, and even the Linux Foundation calls Android a distro.