The JVM does a huge amount more than V8/node.js. If your world consists solely of shuffling bytes around a network then node.js may be a good solution, but it doesn't extend much further than that. For example, I wouldn't want to write a machine learning algorithm in Javascript, nor would I want to write a storage engine, nor a ... you get the idea. Furthermore, while node.js may be growing quickly (easy when you're small!) the development of the Javascript language is taking a rather torturous route as the various vendors play games at the Ecmascript table.
To return to the article, what I really want from both the JVM and Javascript is tail recursion. I'd also like proper lexical scoping in Javascript, though that isn't so important. I don't view Java or Javascript as languages you write but rather languages you compile to (well, you compile to bytecode for the JVM, but hopefully you get my point). Scala and Clojure make mighty fine Java replacements; I haven't seen anything yet for Javascript that is much of an improvement.
Could you list some reasons why you wouldn't want to write a machine learning algorithm in Javascript, or a write storage engine nor a ...? Lack of libraries? Too high level? Or do you not like the syntax/semantics/...?
To return to the article, what I really want from both the JVM and Javascript is tail recursion. I'd also like proper lexical scoping in Javascript, though that isn't so important. I don't view Java or Javascript as languages you write but rather languages you compile to (well, you compile to bytecode for the JVM, but hopefully you get my point). Scala and Clojure make mighty fine Java replacements; I haven't seen anything yet for Javascript that is much of an improvement.