That only holds true for the smallest tier of open source projects. Past a certain point of complexity, it's unlikely you can expect the robot to read your mind well enough to provide something of high quality and 'outstanding for just you'.
The Zig project is certainly far beyond such capability.
You have to push the robot to be as fanatical as you are. It holds so much back, always aiming to do the simple normal thing that most people do, rather than the top-notch stuff it knows.
I'm finding this out the hard way. I set out to build a 1 page app. I thought it would take a day. It's 98% vibe coded at this point. Even with AI implementing everything, its taken several weekends and many evenings. And not because AI is doing a bad job its just that as i see it come together, i have more and more feature requests. I've got a couple dozen left but I can't just let the AI chew through them all at once. Im effectively QA now. Have to make sure everything is just right.