Apple says the future is C++ and Swift.

Microsoft says the future is a mix of constrained C++ (Core Guidelines), Rust and AOT C#.

Google says the future is C++ and Java (as of Treble) on Android, with Go, C++ and Rust on ChromeOS and Fuchsia.

ARM says C++ on mbed.

GenodeOS says C++ and Ada.

Newton, Symbian, Bada and BeOS used C++.

C is married with UNIX, they were born to each other, other OSes have long followed other paths.