Well python allows for type annotations as part of the language; javascript does not, so the compilation stage in typescript is just about erasing types for the most part (typescript tries to have minimal impact on the runtime). It just seems like a worse option than typescript's syntax. Bun runs typescript natively without doing any of the type checking
Even though type annotations are part of the language now in Python, they aren’t used by the runtime so it is still essentially the same as jsdoc or sorbet style type checking. More like a really powerful linter than a transpiler like typescript.
Before type annotations were officially added in python 3.5, you could still use mypy for type checking. The only difference being that the type hint format wasn’t standardized across tools.
JSDoc is strictly less powerful than TypeScript though. For example, more complex types as well as template literal types are impossible to have in JSDoc. It is simply more ergonomic to use TypeScript instead of JSDoc.
There are tools that check whether you are using your types correctly. They work like linters, where you get hints in your IDE and you can run it across the whole project looking for problems when you want to.
The difference between this approach and the typescript approach is that typescript isn’t valid JavaScript, you need a build step that converts it. JavaScript with JSDoc type annotations is valid JavaScript, just with special comments in it, so it doesn’t need to be converted before it is run.
This is how type checking works in python and ruby, rather than there being a compilation step like typescript.