I'm kind of surprised that the Go creators were surprised by this.
Like I know they didn't like C++, but Go is by no means a replacement for C++ despite whatever was said about "building a better C++/Java".
It took so long to pick up generics that Rust was already around and the logical next step for C++ developers by the time that happened. And that's only scratching the surface of why people choose C++.
On the other hand, having a more performant "simple" language that directly supports concurrency and lets you compile to native code without a ton of ceremony could be very helpful indeed if you're a Python dev who need to take an app to the next level without having to learn intricacies of C FFI or the GIL.