Look at that buried lede at the end of the article. 83% (10 of 12) of the Developers left the company after moving to Elixir:
Just as Elixir slashed server costs, adopting it also helped reduce Amplified’s payroll. Before the transition to Elixir, Amplified needed a team of 12 developers. After the switch, however, Grainger found that he simply didn’t need to rehire after team members moved on to other roles.
Now just two developers do the same work Amplified used to need 12 to accomplish.