I don't see what's so difficult. If it was technically possible to run programs that have type errors in other languages, they would have the option to ignore type errors too, because it's convenient.
Typescript also ignores errors (generating js output for you to run) by default, so what's the point if it's not enforced?
As stated in the typing documentation [0]: "the only legal parameters for type are classes, Any, type variables, and unions of any of these types".
[0] https://docs.python.org/3/library/typing.html