No one is arguing that dynamically typed languages are all going to die out (though CoffeeScript and Perl certainly aren't doing well). Languages almost never die. People are still writing COBOL.

But the relative share of programmers writing code in statically typed languages appears to be increasing. When the web got big, there was a very rapid growth in dynamically typed scripting languages: Perl, Python, Ruby, etc. Then, when client side web development became a thing, JS got huge and then CoffeeScript.

In the past decade or so as developers have moved to writing larger more performance-intensive client-side applications (read: mobile with touch UIs running at 60 FPS), there is now a turn back towards static typing: TypeScript, Kotlin, Swift, etc.

Also, the sophistication of static type systems is increasing. Generics are now a given, control over variance is increasingly common, as is static control over null references.

This doesn't mean the graph will go towards static types forever, but it certainly appears to be right now.