C is not going anywhere. Neither are C++, Java, and JS (less sure about TS).

One reason is that we've built most of the foundations of modern software already in these languages. New apps pop up all the time but they all rely on ffmpeg, etc.

The only way for a new language like Zig to cement itself is to build foundational software that other programs depend on. I don't think even Rust is moving in that direction (lots of Rust apps, but not so many libs I've had to use in my programs that were written in Rust).