A lucid and clear analysis of the current situation of gradual-typing: https://blog.sigplan.org/2019/07/12/gradual-typing-theory-practice/
It explains why gradual typing spread so well, the type system ideas they have invented or improved to support some of the many unusual ways dynamic language programmers use their languages, why some of the basic purposes of gradual typing (type soundness) are currently under-developed in practice, and how this problem could be solved in future.
One thing it doesn’t discuss is if and what kind of effect and consequences all this world of gradual typing will have on statically typed languages, like Rust. Do you have ideas?
I expect that (as it usually happens) programmers that have used gradual typing a lot will start asking for some of those new type system tricks in statically typed languages too, but most of such gradual typing handy features look unfit for statically typed languages.