The moment anyone saw 7M lines of Java vs 85k of Scala, anyone worth their salt would have known that Scala usage was not going to be successful. When you have that level of Technical Debt, it makes little to no sense to implement these things in another language (no matter how strong the interop may be). Reeducating hundreds of programmers to write idiomatic Scala at their natural peak productivity was bound to be a disaster.
