> At least for my operation it looked very much like I would really need to become a BEAM vm expert to make sure things ran smoothly
From someone with zero experience in building concurrent systems: isn't this true for every sufficiently complex system? If your system is complex enough, then no general framework will help much, right?
At some point sure, but I can get concurrent systems up and running pretty easily in Go, C# and Rust without going too deep into the underlying details of the asynchronous framework. Erlang's VM does a lot more than any of those frameworks or runtimes do though because of how it handles per process garbage collection yet globally shared binaries, the preemptive scheduler and how it balances process load, the hot-reload capabilities etc... It does a lot of things really well but there's a lot of magic behind it, and I seemed to brush against that much faster than I have in other languages.
From someone with zero experience in building concurrent systems: isn't this true for every sufficiently complex system? If your system is complex enough, then no general framework will help much, right?