Go is a reasonably performant language that makes it pretty straightforward to write reliable, highly concurrent services that don't rely on heavy multithreading - all thanks to the goroutine model.
There really was no other reasonably popular, static, compiled language around when Google came out.
And there still barely is - the only real competitor that sits in a similar space is Java with the new virtual threads.
Languages with async/await promise something similar, but in practice are burdened with a lot of complexity (avoiding blocking in async tasks, function colouring, ...)
I'm not counting Erlang here, because it is a very different type of language...
So I'd say Go is popular despite the myriad of shortcomings, thanks to goroutines and the Google project street cred.
The change from Java 8 to 25 is night and day. And the future looks bright. Java is slowly bringing in more language features that make it quite ergonomic to work with.
I have no desire to go back to Java no matter how much the language has evolved.
For me C# has filled the void of Java in enterprise/gaming environments.
Modern Java communities are slowly adopting the common FP practice "making illegal states unrepresentable" and call it "data oriented programming". Which is nice for those of us who actively use ADT. I no longer need to repeatedly explain "what is Option<?>?" or "why ADT?" whenever I use them; I could just point them to those new resources.
Hopefully, this shift will steer the Java community toward a saner direction than the current cargo cult which believed mutable C-struct (under guise of "anemic domain model") + Garbage Collector was OOP.