That collaboration thing is why Actix exploded I think. While mostly an isolated incident it does show some clash between the author's values (and possibly the author's employer's (MSFT) values) and the values of the general Rust community. I would not say that reflects on the maturity of the langues or ecosystem.
In Go a lot of stuff is Google dictated. In Rust it's a true open governance innovation project (looking to become a non-profit). Since the Go is a very specific language --made for networked apps and only has one way to do concurrency-- and Rust very broad --a true general purpose prog lang-- it is easy to see how Go mature so quickly (not much to mature) and also why it got a bit old so quickly as well (ignores most innovations in computer science of the last decades).
Just because it is used most for "network apps" doesn't mean it's limited to that. On the other hand, you could argue that Rust is a wrong fit for anything _except_ performance-critical applications, because for anything else it's not worth to saddle yourself with the added complexity.
> and Rust very broad --a true general purpose prog lang-- it is easy to see how Go mature so quickly (not much to mature) and also why it got a bit old so quickly as well
This simplicity is the thing Go opponents like to point out (or mock) most, and what Go fans actually would tell you is one of the best features of the language. It's actually refreshing to have one language that doesn't try to be everyone's darling by implementing every conceivable feature - we already have enough of those, Rust, C++, Java etc. etc. But you don't have to take my word for it, you can also read the first sentences from this blog post: https://bradfitz.com/2020/01/30/joining-tailscale - he puts it better than I could...
Google explicitly shown no intent to make Go a fit beyond network apps. You can hack something into doing more than originally intended, but then you are usually operating "outside of warranty".
> On the other hand, you could argue that Rust is a wrong fit for anything _except_ performance-critical applications
Well, Rust does more than C-level high perf. It also allows for very safe/maintainable code that's high perf. Both of these are not something like a special feature, nope, ANY software needs to be high perf, bug free and maintainable to some degree. And as the size of the codebase grows, lack of these properties in a languages rears is ugly head.
The added complexity cost, as you mentioned, is IMHO not a real cost. It's more like an investment. You go with Rust, you have to pay up front: learning new concepts, slower dev't, more verbosity/syntax/gibberish-y code. But once the codebase grows, you(r team) have grown accustomed to this and you start to reap the benefits of Rust's safety, freedom to choose your concurrency patterns, maintainability and verbosity.
Now I do want to point out a REAL cost that was not mentioned yet, that Rust brings with it much more than Go: compile time. This sucks for Rust. Given the complexity of Rust, I dont expect it to ever come close to Go's lightning compiles. It will improve/ it constantly improving. And IDE features that prevent compiles (e.g.: error highlights) are maturing and will help too. But this is a big reason for picking Go.
Your Jedi mind trick about Go's "simplicity" does not work on me :) ... It's fast compiles (a result of simplicity) are the bonus. Not being able to use the language beyond network apps or go-routine-concurrency are simply a minus for every learner (not for Google as a creator), as you limit the use of your new skill. The reason they kept the 1B$ mistake (null) in there is simply unforgivable.
And if Go will never add features we have to see. Java also intended to stay lean, well...
Both have ups and downs. Rust definitely has immature web service ecosystem and it's a result of immature async i/o ecosystem. At the same time go has those things otb.
