Here's a counter-argument.

    var x = new Foo()

...is almost universally recognizable, and leaves little guesswork about the intent and meaning of the code. There's a lot more ambiguity encountering this:

    var x = foo()

What am I getting back? A primitive value? An instance? A singleton? I have to go peruse the docs. `new` can definitely be abused to do non-intuitive things, but it's still a powerful signal to future readers of the code.