The thing with Typescript is that it is only a fancy JavaScript linter, so the only way to justify newer releases is to keep adding up the type system, there is nothing else when language features that aren't type system related are supposed to come from JavaScript evolution.
So they either say they are done, or keep adding type theory stuff until it implodes, I fear.
Actually I am looking forward to type annotations in JavaScript now in the roadmap, being good enough for general use cases.