To be fair, what made Elixir take off, other than syntax there is also the developer experience overall, including documentation, package manager, unit testing framework out of the box, web-framework initially inspired by Rails etc.
Though, slightly off topic, but worth mentioning, that both Erlang and Elixir communities support each other very well. For example, now not only elixir is built on top of Erlang, but also Erlang adopts some things from elixir, such as monadic expression `with` from elixir inspired `maybe` in Erlang, or starting OTP27 Erlang is using ExDoc introduced by Elixir to generate documentations.
Though, slightly off topic, but worth mentioning, that both Erlang and Elixir communities support each other very well. For example, now not only elixir is built on top of Erlang, but also Erlang adopts some things from elixir, such as monadic expression `with` from elixir inspired `maybe` in Erlang, or starting OTP27 Erlang is using ExDoc introduced by Elixir to generate documentations.