Erlang (and by extension Elixir and LFE) has "nailed" it by making the actor pattern first class. Go's channels are great, but Go itself is quite low level. Also you should checkout Clojure's core.async to see what improved channel constructs on top of a high level, lock-free, multithreaded language core looks like.
Part of the problem with Python ecosystem is the insular mind set of its proponents. Python fanboys have no interest in going and seeing whats on the other side. So the platform has become a bit of an echo chamber with Pythonistas declaring their clunky approaches the industry best.
You can see this by looking at how little love a CSP solution for python gets [https://github.com/futurecore/python-csp] verses the enormous buy-in it's more popular frameworks receive.
How is it possible then that core.async works on javascript platform, a platform that has no mutexes?
Maybe there is a lock to implement the thread macro (clojure only), but then that uses native threads. How would you propose to handle access to channels between native threads without locks?
As far as I know there is no locking performed in asynchronous code implemented using the go macro. The go macro is a macro that turns your code inside out into a state machine, is it not? Each <! and >! point becomes and entry/exit into that state machine. There are no locks here because the go macro can essentially "rewrite" your source code for you and there is only a single thread of execution through the interconnected state machines.
There are obviously platform-specific implementations. In Clojure, core.async utilizes locks, and the original comment wasn't referring to ClojureScript.
Part of the problem with Python ecosystem is the insular mind set of its proponents. Python fanboys have no interest in going and seeing whats on the other side. So the platform has become a bit of an echo chamber with Pythonistas declaring their clunky approaches the industry best.
You can see this by looking at how little love a CSP solution for python gets [https://github.com/futurecore/python-csp] verses the enormous buy-in it's more popular frameworks receive.