Most certainly. Elm uses compiler magic to achieve certain results and makes no effort to hide it; ultimately the objective of the language is to be simple and approachable, not all-powerful. My article was a thought exercise, by no means I’m suggesting this is a viable alternative to proper Typeclasses.
I will say that I’m beginning to suspect these limitations are playing a major role in keeping Elm from reaching a wider success as a programming language. Maybe the ability to create truly flawless abstractions for user libraries is more important than I’d imagine.