I'm confused about the comparison here. I've never heard of Mojo before, but reading this and all the discussion of the main languages on Apple's platform, you'd think that Mojo was somehow an alternative for development on iOS or macOS, replacing Objective-C and Swift, like the post is making a case that it is better than Objective-C. But it appears to have nothing to do with this, so the juxtaposition feels odd. There are a great many two-language-problem situations in the wild (Clojure/Java, Elm/JS, etc) and each features a solution that is somewhat tailored for the specific use-case or platform. Seems odd to compare one of these use-cases with another when the situations so widely vary.