[somedudethere]

I think one of the primary benefits to ELM, etc is the typechecking, which you lose if you use FFI to call outside JS.

Once you dont need jquery and you actually have a standard library, 2 of the largest requirements to the existing ecosystem (JQuery and Underscore.js) are no longer needed.

Elm looks to handle much of he DOM and events so I doubt you would need React.js or Angular, which just leaves your datastore.

(to better put it, much of the packages in Javascript are there because the language itself is insufficient to describe DOM interactions. Elm was created explicitly for the web thus removes the need for many packages)

[lolive]

The other issue is the untyped nature of JSON. Interacting with JSON from Elm does require a lot of Encoder/Decoder. May be JSON/LD could be a nice improvement for that, but it will require a significant effort to be broadly adopted.