TypeScript is my favourite programming language but I don’t see it replacing JavaScript. I think it’s good to have options.
Deno is looking quite promising as a native TypeScript engine for the backend.
We just switched from js to ts a couple months ago and it's been nice having the familiar oop paradigms to write large applications. As a superset of js, I think it makes sense for all js developers to get a grasp of ts, as it only provides more power and organization at the cost of being more strict than js. Plus, all your js code still runs under the typescript compiler.