C#'s runtime got generics in 2005 whereas Java still just has compiler-only sugar. It's a rather significant difference in the quality of the implementation. Not just for things like reflection but also means List<T> ToArray actually can return T[] instead of Object[].

It also means the .NET ecosystem didn't need the inline+reified kludge that Kotlin came up with https://kotlinlang.org/docs/inline-functions.html#reified-ty...