Earlier quoted context omitted.
For one Elixir is very slow compare to Go.
For what purpose? See: https://stressgrid.com/blog/benchmarking_go_vs_node_vs_elixi...
If the article had gone up to 250K connections, Elixir would have fallen down similarly to what happened to Node... although the reasons for Node being unable to keep up were unclear in the article, and I think warranted further investigation that the article didn't do.
For another comparison, feel free to click around on the tabs here: https://www.techempower.com/benchmarks/#section=data-r17&hw=...
The plaintext benchmark is about as far from a computationally intensive task as you can get... it should basically be network-bound, supposedly an ideal task for the BEAM VM, yet the results are clear.
If you turn on additional languages and frameworks, you'll note that Elixir or Erlang are significantly faster than, say, Rails, but Elixir or Erlang are a good 5x to 25x slower than Go.
People have built massive, successful companies on Ruby on Rails, such as GitHub, so don't think that I'm discounting these languages wholesale. You just have to accept that you will be paying substantially higher infrastructure costs if your infrastructure needs begin scaling beyond a single server. If you think that Elixir or Ruby or whatever else is the secret sauce to make your company successful, go for it! But those are a lot slower than Go or Rust or other very fast languages.