Competitor to TypeScript? Any insights into advantages / disadvantages?

No need to look at google trend, Typescript is too big by now, many libraries client and server use it out of the box, and the possible advantages of this competitor look very small in comparison.

I even don't understand why browser don't start to work on supporting it directly, maybe google/chrome have something in mind and slowing down its integration, or it's because of performance issues.

> I even don't understand why browser don't start to work on supporting it directly

https://github.com/tc39/proposal-type-annotations