A lot of Graydon's ideas feel like interesting extensions to ML-style languages. I bet if he had continued down that path, it would have been a lot more of an experimental language with a hodgepodge of different ideas. Which is totally valid (you need these languages to test new paradigms and features), but definitely would not have become mainstream.

Basically, I view Grayson as a leader who set the tone for Rust being a language that was willing to take ambitious swings on cutting edge features. But I don't think he would have been the person to eventually make the cuts and compromises necessary to hew the language into a cohesive, mainstream language. Rust ending up as a replacement C++ helped it not only determine which features to keep and which rules to follow, but also helped it create the right pitch for developers to use it.

This does lead to a larger question about BDFLs. Perhaps, like CEOs, the BDFL you want when you're starting a language is not the BDFL you want when you're maturing a language, or maintaining a language. Especially around feature selection, in the beginning it may pay off to add a lot of features based on user feedback, but later on it may be better to push back more. And from a psychological standpoint, I have wondered about the pressure of being a BDFL. Grayson has been open about stepping down partially due to reaching his limits, and I suspect other BDFLs have thought about it too. The job sounds exhausting and thankless. At a certain point, wouldn't you want to leave and start a new project? And wouldn't we want the person who had success once to give it another shot?