It seems that when implemented correctly, running full-stack Elixir can greatly simplify complicated distributed systems. In-memory storage can replace a cache, and the architecture itself can replace a message queue. Horizontal or even vertical scaling can replace complicated scaling mechanisms. There are plenty of advantages to running data pipelines in parallel too.
There's also a huge trend now away from managed cloud services (ZIRP), and it seems like Elixir with a database on the same machine or network could deliver great performance and scalability.
So why don't more people use Elixir? I've read some complaints about the lack of static types or not having as many developers. But if those were the only constraints, one would think that they could be overcome, or some service could just greatly simplify Elixir deployments.
I built 3 production projects in elixir around 2015-2018, and it was a blast to learn and work with. Those were interesting projects that were a great fit for the stack. One was March Madness bracket game which required a huge throughput on day one, and another was a football game audience play calling each play from their phone as the team is playing live at the stadium. This one needed a lot of timing coordination and poor connection handling. I even put out an open source fast/customizable leaderboard on top of ETS.
However, I didn’t feel the need for this stack on most projects, and if I’m totally honest, I never got good at the novel way of building applications in it.
While it was very enjoyable, everything felt a little awkward. Even 3 years in I constantly felt that I’m not doing it right, and I’m fighting the language to do data transformations in a purely functional style. I never got used to writing Ecto queries, and always had to look up their syntax. Plus, there didn’t seem to be a good architecture story, just isolated praise of OTP. And Phoenix further fueled the confusion, making it hard to understand whether I’m supposed to reason about my app like a Rails app (just build controllers, models, and views) with no regard for processes, or I should orchestrate some creative supervision trees, that I can’t even tell how they would be arranged in a typical web app. Going back to Ruby on Rails was kind of back to super productive comfort zone after a bit, and I just continued staying there.
I’m still looking back at Elixir with nostalgia, wondering if I’m going to have a chance to go back to it and really make it an extension of my arms/brain like Ruby had become. And whether I can do all that amazing supervision-based architecting I keep theorizing in my mind. I loved Dave Thomas’s vision (and agreed with his controversial takes) and really wished I could get as good as Sasa Juric at really deeply reasoning in this framework. Maybe one day.