Because it isn't memory safe. I honestly think it's beyond the point of "irresponsible" and well into "negligence" that we're still developing unsafe technologies - people are being harmed by this choice. It's one thing when you have to target specific platforms and maybe Rust wasn't an option or whatever, but the reasons to choose unsafe languages at this point are vanishingly small.
Zig is very cool, I love many aspects of it. I'll never touch it, I'll always advocate against it tbh. I'd probably advocate that software written in languages like Zig be flagged for FEDRAMP and other environments since devs seem to not care unless they're legally barred from making these sorts of choices.
No system will likely ever guarantee that software does what you expect. That runs into the halting problem, and practically runs into a verbosity problem. But that doesn’t mean systems that give scoped guarantees aren’t amazing for building (and iterating on) reliable software.
this is an insane take
For example, I find Rust to be far too similar to C++, and it shares most of the problems I have with C++ only with much lower adoption. I'm not saying I'm ready to make the switch, but at least Zig offers a different approach that's intriguing to me.
Do not try it if you are scared of memory management and memory leaks.
For small, short game dev, or even smaller embedded projects, this ends up being a wonderful way to live as often times you're trying to eke out performance in ways that would require breaking out of whatever type abstractions or using unsafe.
For long-lived systems, for systems that need to have lots of people with various skill levels work on them, for a mature ecosystem, for a language/standard library with stability... You probably don't want to pick Zig right now. Some of these points will change over time with Zig becoming more mature, some won't. Zig will always be super cool to build things in.
As far as most low-level programmers not liking Rust like some other commenters say, lol, lmao even.