I wouldn’t worry about that. There’s plenty of software yet to be written, in many languages. If anything, Rust’s success has shown that it’s definitely possible for a new language to succeed if it offers something new.
The other tailwind for Zig is that it’s easier than ever to translate an existing codebase with tests into a new language with AI.
Their own libc project is wicked. They are gradually replacing C implementations with zig and in the mean time the C implementations effortlessly link and compile in the same compilation unit as the zig code.