> You can pull this off in other languages via careful attention to the details of your request-handling code. But, the creators of the Erlang language and foundational frameworks have set their users up for success via careful attention to the design of the system as a whole.

+10. So many people miss this very important point. If you have lots of mutable shared state, or can accidentally leak such into your actor code then the whole actor/supervision tree thing falls over very easily... because you can't just restart any actor without worrying about the rest of the system.

I think this is a large (but not the only[0]) part of why actors/supervisors haven't really caught on anywhere outside of Erlang, even for problem spaces where they would be suitable.

[0] I personally feel the model is very hard to reason about compared to threaded/blocking straight-line code using e.g. structured concurrency, but that may just be a me thing.