It's plausible that OP's company is succeeding with 100% AI-generated code, even if Bun fails, but it's also plausibly false. Anyone can claim anything on the internet, what separates BS from reality is evidence.
I didn't write that Bun's rewrite absolutely proves or disproves OP's claim, I wrote that it provides evidence; it does, much more than OP's word.
It's also plausible that OP's claim is true, but only because despite being in a "big tech" company, they've been working on small self-contained repos, throwaway scripts, etc. The implications of this would be much different than what their comment suggests, which is another reason evidence matters: it forces them to narrow their claim, because anyone can make an overzealous claim from a small example.
People write code differently, AI models write code differently, AI systems write code differently, companies create systems that write AI-written code differently, etc.
The system that wrote Bun bears no relationship to the system that writes OP's code.
Making such absolute statements about AI-written code is as dumb as making absolute statements about human-written code on the basis that it's "human-written".