Rust's big tentpole is "no memory management bugs, everything must be provably safe", whereas Zig is very proud of "no memory management, you have full control but you have to exercise it". I don't feel as though these are competing for the same audience or mindshare.
I've used Zig a big (while trying to contribute to ghostty, at least), and it's an interesting language that I like the aesthetics of but I don't want to use. I use Rust for things because it's so specific about what it wants from you and won't let you go off-script, and frankly I find that very beneficial for myself as someone coming from Python, Javascript, PHP, etc. where you just let things fall out of scope and it's not your problem anymore (usually).
I share your complaints about the tools you came to Rust from, but the philosophy of not letting you go off script is great until it doesn't work for you. A lot of the reason some of us use the more flexible languages is because we've been in situations where a language and its ecosystem either won't let you do something outright or not without significant pain. Often when everything is on fire and your customers are cancelling contracts. You can't afford to wait for the core team or community to come in and save you in these situations.
Having access to work around your problems is also the source of a lot of the pain you're talking about, but at least you get to stay in business to solve that problem tomorrow.
To a very large degree, a lot of the Rust evangelists that I encounter in the wild are either hobbyists, academics or paid open source contributors at large companies. Most of the discussions I've seen wrt Rust at companies with actual deliverables stop at "Rust? Absolutely not.". Except for a very narrow set of systems where you want the kind of guarantees that Rust provides as a primary feature. For more general situations, the tradeoffs often aren't worth it.