That is an eloquent way of re-writing the history of Microsoft stealing Java and not being allowed to get away with it.
This cracked me up
I think (but may be wrong) their concerns are about the insert part. C# always had structs, Java wants to add them in a backward-compatible way. They want, for example, existing generic container classes pulled in from a .jar (i.e. already compiled) to support Java value types.
All the types that are value types in semantics, e.g. Optional, should be proper value types on Valhalla.
Additionally, they should be compatible with existing code that expects them as parameters, fields,.... without being recompiled from source.
If it is a complete new type without backwards compatibility, no one is going to adopt it, other than a few niche cases.