Statically typed languages increase productivity by catching errors early, but decrease productivity by making users jump through hoops.

e.g. at one end of the spectrum is Java, which everything has to be a class. Even if you want to write a function, it has to be expressed as a static method in a class. In Java it's just not possible to implement ideas in the most obvious way, it has to be done in the Java way.

Conversely, TypeScript was designed to work with JavaScript (which is very dynamic), so it has a very capable structural type system. The productivity penalty is negligible.