I like Zig, lots of great features that work in unison. However the worry is by the time it reaches v1 Rust will have consumed the space that C/C++ used to. I think it will be a mainstream language though and gain a lot more traction after v1. There is also the issue of will people actually code by then.
Given that Rust is quite an old language now and its adoption is still so low, I don't think that should be much of a worry, although that doesn't mean Zig will be the option of choice, and not stabilising is certainly not a good sign. At Rust's adoption rate, a language that hasn't been invented yet and that would show a more normal rate of adoption for a popular language could easily overtake it.
> There is also the issue of will people actually code by then.
Now that could be a bigger issue. :)