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.
Which Google uses far more commonly than Go, still to this day.