Many of the Scala projects got people fired. Something the Scala devs largely ignore. Plus Scala support is truly awful even by the low standards of an OpenSource project. Then there is the fact that the Scala specific libraries are largely dead.
Scala had/has a lot of promise. But how the language is marketed/managed/maintained really let a lot of people down and caused a lot of saltiness about it. And that is before we talk about the church of type-safety.
Scala is a more powerful language than Kotlin. But which do you want? A language with decent support that all your devs can use, or a language with more power but terrible support and only your very best devs can really take advantage of. And I say this as someone writing a compiler in Scala right now. Scala has its uses. But trying to get physicists used to Python to use it isn't one of them. Although that probably says more about the data science folks than Scala.
PS The GP is right, they should have focused on support and fixing the problems with the Scala compiler instead of changing the language. The original language spec is the best thing the Scala devs ever made.