PEOPLE make stuff, people use stuff, and people are ultimately the ones who are going to pick and choose which stuff gets made, used, adapted, enhanced, and carried into the future.
AI is an inherently anti-social, anti-human technology, and this rewrite is the perfect example of that.
Assessed from the perspective of "technology in a vacuum", of course. it's a success. He did the thing that transformed the thing from one kind of stuff to another kind of stuff. It still does all the things it did before, and in many cases with better stats than it did before.
Assessed from the human angle, and especially the angle of Bun as a community, I would bet money that this rewrite -- executed by nobody for nobody, built and maintained by machines, maintainable only by machines -- has killed the entire project.
Maintainable only by machines, because anybody with any knowledge, experience, or investment into Bun as a platform, or who contributed patches themselves, or whoever had a question about how it works and went "Hmm, I'm gonna go into the codebase and take a look at how that happens", they all got slapped in the face and summarily kicked out of the tent with the rewrite.