You want to have your cake and eat it, too. You've just argued for both viewpoints (TS is bad because it does X and because it doesn't do X).
Just be honest and recognize that you dislike Typescript and/or Microsoft. Nothing to be ashamed of, many decisions in tech are based on feelings as much as on cold, calculated decisions.
What? I want TS to be different lang transpiled to JS or be annotation to JS but it is: Embrace and extend existing Standard (superset) and when everyone will write TS it will come to Extinguish step. (I like C# and don't like Windows my like not like to MS tech is 50%)
So there is no hard promise of TS backward compatibility ?
Sorry but whole TS looks like another EEE - MS will/can argue on some further JS changes for/against based on existing TS codebase. I hope I'm wrong here though.