Maybe it's one of the cases when techies call the shots?

I can understand people being more sold on Rust compared to Zig -- there are legitimate differences on the memory safety front and I can see how people will prefer one or the other.

Plus I believe Jarred (Bun's main dev) went out of his way to explain why he chose Rust over Zig in his blog post.

Of course the marketing angle might indeed be the explanation; not arguing against that, I simply followed with interest and Jarred seemed very reasonable to me.