Sublime success shows people do need those 0.01 seconds saved (well, actually it is often not just 0.01 seconds, but a lot more - VS Code is sometimes laggy and that's really annoying).
If I have big files to open, or I want to do some text manipulation, then ST is what I reach for.
"Completely destroyed" is a bit much, maybe shifted to a different use-case for some people, but for a quick editor that offers a pretty damn good environment to work in I think it still has its place.
Anyway, the author wanted to write a desktop app in Rust. What's the issue with that? A few years ago, we'd have the same but "written in JS", "written in Ruby", "written in Python", ... I agree that it's more important for the author than for the end-users, of course.
maybe this is just the new vim/emacs war :)