Switching to Go or Rust would only make sense if performance were the main priority, which doesn’t seem to be the case. Their current setup lets them ship quickly. A rewrite in Go would likely slow that down.
Codex moved to Rust, and you can see the trade-off. Performance improved, but release velocity dropped. They’re also still catching up to Claude Code, so they don’t face the same pressure to ship as fast.
The bun people likely have some fucked up incestial business relationship with some >dev manager at Anthropic and the same pattern is repeating. Only this cycle it's going straight to acquisitions, which honestly seems like a worse strategy and Anthropic will def can the bun engineers in less than <3 years or whenever they face an actual budget crunch that they can't stave off with more gulf money.
"The key point here is our programmers are Googlers, they’re not researchers. They’re typically, fairly young, fresh out of school, probably learned Java, maybe learned C or C++, probably learned Python. They’re not capable of understanding a brilliant language but we want to use them to build good software. So, the language that we give them has to be easy for them to understand and easy to adopt. – Rob Pike"