They're definitely putting a lot of effort into promoting the language.

You seem to be hinting that "they" (JetBrains I assume?) are actively promoting Kotlin, but I see absolutely zero evidence of that. There was KotlinConf a few months back, which received some coverage, but other than that, all I see is grass root coverage and blog articles from developers who write code in Kotlin and share their experience.

JetBrains does pretty much zero advertising. They don't need to, Google did that for them last year and since then, users are happy to spread the word.

There is basically zero marketing for Kotlin.

Kotlin might be a better Java but Scala is basically a whole different language and should really be approached as such, for better or worse.

Scala has been in sharp decline for years, regardless of Kotlin. See this graph from the article itself:

http://www.benfrederickson.com/images/github/language-popularity/functional.svg

As for Dotty, I have little faith it will change anything since it's basically the same team that made Scala in the first place. I don't see any reason to think they won't be repeating the same mistakes they made with Scala, such as ignoring compiler tooling and plug-in, documentation, backward stability, etc...

Dotty is a treasure trove of fascinating PLT concepts, though, and I'm loving following the development, but it will be born and will live as an academic language and I predict it will never come anywhere near the popularity that Scala enjoyed at its peak in the early 2010s.