No, but for a different reason. Right now relying solely on WebAssembly where you can use JS is dead in the water (how many websites still keep up IE support).

No, but for a different reason. Right now relying solely on WebAssembly where you can use JS is dead in the water (how many websites still keep up IE support). The question will be in a few years (especially once WebAssembly DOM support comes in). Even then, there's so much JS in the wild that only a depracative step (JS is no longer supported) will kill it. It's like Clojure, Kotlin, Groovy and other JVM languages. Even if they are better by a long shot than Java, the legacy factor will keep JS (and Java) alive for a long time (and the fact that JS doesn't require a compiler or environmental).