Agreed. The DB is the bottleneck way before the code architecture. But that is a "solved" problem from a deployment perspective. All the Cloud providers have managed Postgres that scales to petabytes and millions of transactions per second. And the part being discussed in the article is the Microservices. Where Elixir/Phoenix shines at delivering the benefits of Microservices i.e. scaling a specific function in your codebase to multiple processors/instances while still being easy+fast to run on a single Dev machine without hundreds of Docker processes.

Not sure just how solved that is for write heavy workloads. It seems possible for a medium sized very successful company to hit fundamental limits requiring some architectural changes. Eg https://www.figma.com/blog/how-figma-scaled-to-multiple-data...

Sorry but what are you talking about? Microservices in a monolith without containers? How does that even work?

Erlang/OTP (and therefore all BEAM Languages such as Elixir) have a supervision tree which means that each module in a monolithic application can be run independently in as many processors/machines as required. Essentially you get Kubernetes + Docker for free (virtually zero overhead) inside the Erlang VM. See: https://blog.appsignal.com/2021/08/23/using-supervisors-to-o...