[inaseer]

That's a fair point. Having said that, it's also interesting to realize that most distributed systems (which are concurrent by their very nature) don't have that luxury. Our micro-services interact with databases, event queues, blob stores etc and each of those external entities is shared mutable state. Furthermore, services can crash at any time and can't start from a clean slate (unlike in-process concurrency which doesn't have to worry about that). My meta-point is that while I agree with your sentiment, the reality of modern day services is that you are _forced_ to reckon with mutable complexity when designing distributed concurrent services (and more and more of us are doing that with the shift to micro-services in the industry)