It is a remarkable for one person to create a language, runtime, repl, debugger, compiler to another quirky language i.e. JS that is usable to the point that people are doing professional work in Elm. Also the compiler produces easy to understand messages.
Evan has made Functional reactive programming more accessible. I don't think I would have a chance to understand FRP at all without Elm. Elm has inspired other frameworks in Purescript and the development of ReactJS.
Sure Elm is not perfect. I found that much of the JS ecosystem not viable in the Elm world, even with FFI due to the purity of the virtual dom. I can't just go and easily chuck an impure calendar control in my code.
However despite it's drawbacks I feel the article was a bit strong in putting down Elm, which is sad because I think there are the seeds of some great future languages and ideas in there.