You may or not be right, but Typescript seems to be gaining a reasonable amount of attention and traction outside Microsoft, so I suspect its type system may be "good enough" to add a decent degree of type safety while still staying close enough (for better or for worse) to vanilla Javascript that developers, CTOs, etc. aren't put off by the perceived difficulty/risk of a totally new language (also I guess the Microsoft backing counts for something).
Typescript may not be perfect but I'm glad to see it getting more attention as I think it can bring a significant quality improvement to a code base for a fairly small investment of effort.
There are enhancements to the type system on the roadmap, for example support for non-nullable and variadic types: https://github.com/Microsoft/TypeScript/wiki/Roadmap
Typescript may not be perfect but I'm glad to see it getting more attention as I think it can bring a significant quality improvement to a code base for a fairly small investment of effort.