It is not about one ruling them all. But people will simply coalesce around one language and communities of the remaining languages will simply dwindle. They will all still exist but there is a reason why only few languages are mainstream. And the three I have mentioned will be essentially competing in the same playfield. Unlike Rust, JS or Go, for example, as they already have their niches. All of the three are here to compete for the place in the low-level language tier list.