Java, Kotlin, C# and TypeScript are led by companies that want usage. Scala was and still is primarily an academic exercise. Same problems as with Haskell - the leadership are paid to add random optimised-for-sounding-clever ideas to the language, not design a language in the gestalt that optimises for user success.
In particular TypeScript is not a research language and therefore the documentation, marketing, leadership etc doesn't strongly emphasise convoluted FP type theory. That means the sort of people who really want to go wild with that stuff stay away.
Scala's origins at EPFL under Odersky does give it a disadvantage given the history of academic origin languages in industry. OCaml was made at INRIA and it seems to have suffered the fate of becoming a niche language and toolchain for industry programmers. The Limbo programming language from Plan 9 didn't get very far until it was re-adapted and re-imagined as Go which has obviously gotten a lot of adoption from industry.
I'm not an either/or kind of person and don't see why a language suitable for academic purposes can't be broadly useful in industry, but I would also agree that leadership that has little background in certain use cases may not design and orient the language accordingly.
Java, Kotlin, C# and TypeScript are led by companies that want usage. Scala was and still is primarily an academic exercise. Same problems as with Haskell - the leadership are paid to add random optimised-for-sounding-clever ideas to the language, not design a language in the gestalt that optimises for user success.
In particular TypeScript is not a research language and therefore the documentation, marketing, leadership etc doesn't strongly emphasise convoluted FP type theory. That means the sort of people who really want to go wild with that stuff stay away.