I think bun is moving to rust because Anthropic owns it and the devs there like rust. So why would they invest in another implementation? Sad to see a good zig example go, but as soon as Anthropic bought it I wrote the project off.
I am not aure either, but bun wasn't using normal zig and there was drama about upstreaming. Combine that with anthropics desire to show they can help rewrite everything in rust and that probably accounts for some of it.
