A language with no built-in multi-threading capabilities is unlikely to suit every backend. Running multiple copies of the same lightweight process works quite well for stateless http interaction (request -> database -> response), but it's a lot of overhead to cross process boundaries every time you want to run something in another thread.

I also have a question about the loss of mindshare. What new technologies are unaccessible from Java, but are accessible from at least 2 other languages (one of which is TypeScript / JavaScript)? A loss of mindshare would likely mean smart people aren't around to build libraries / integrations to the latest hotness.

My background: Originally a Java developer, now mostly Clojure. Also a Javascript (mostly react) developer.