We could certainly debate the objective merits of Elixir vs other languages (which seems to be the primary discourse in this thread and elsewhere) but hearing subjective developer experiences is also critical.
It doesn't matter if Elixir is objectively better or not, if lots of devs who are exposed to it are having a hard time it's worth asking why.
In addition to developers not wanting to expend additional effort to learn a new language or paradigm, I believe there are gaps in the ecosystem especially around medium-advanced topics.