Diminishing returns of static typing

Yes, there are diminishing returns. But people who are frustrated with Go's type system aren't just blindly pushing for more precise types. They have experience with generics and have decided that the cost/benefit is worth it.

Also, the optional static type systems for languages like Python and Javascript are more precise than Go's. So when you actually decide to apply types to your code, you get more checking than you could ever get in Go.