> Most shops that use Kotlin on the backend also do Android development, as means to do core sharing between backend and Android
None of the companies that I wrote Kotlin for or that I applied to used Kotlin for code sharing between backend and Android. It seems as if you're making a lot of assumptions in this comment thread.
Doesn't change the size of the market share anyway, an assumption done on links I shared, because this is the Internet and we have to prove every little word we write.
Can share more market research reports if you feel like, with similar numbers.
Given that Java is one of the most used languages globally, 10% of it is still significant. It's definitely easier to find a (backend dev) job using Kotlin around here than one using Elixir, Common Lisp or Haskell, yet I don't see you going around bashing those communities.
None of the companies that I wrote Kotlin for or that I applied to used Kotlin for code sharing between backend and Android. It seems as if you're making a lot of assumptions in this comment thread.