Why isn't it a good fit? The design prioritises readability of code that uses generics vs writing generic code (which is in line with the overall language philosophy). It also does it in a way that doesn't impact compilation speed or add too much complexity, which is also in line with the language philosophy.

If you don't like the fact that not all of standard library has been refactored to support the new language features -- I think it'll come over time. Once these features land into the standard library they can't be taken away, so the language authors take their time to make sure it's designed well.

I don't see anything going obviously wrong here.