Still using it to build Kubirds[0] (a Kubernetes operator for monitoring/alerting).

WhatsApp is built with Erlang, as well as RabbitMQ. Discord is built with Elixir.

Some people are starting to build NIFs in Rust with Rustler[1].

Erlang/Elixir and OTP are far from dead. But since there is not a new version every 3 minutes, it's not getting a lot of attention.

  [0] - https://kubirds.com
  [1] - https://github.com/rusterlium/rustler