They don't have a goal of becoming a popular language, though and will continue to work on it as long as there are donations.
They don't care about being mainstream and there are niche companies who appreciate Zig and donate.
Andrew Kelley - An Open Letter to Everyone I've Butted Heads With (2025 Aug 29) https://andrewkelley.me/post/open-letter-everyone-butted-hea...
For real though, if your goal as a language isn't to become popular then why should anyone learn it? Why should anyone spend their limited time building libraries in it when the language isn't likely to grow (and thus is more likely to disappear)?