It's odd because at Google people still write networked servers in C++, which I'd argue, almost no one outside Google does?

Rob probably assumed Go could displace this. And it's not unreasonable to assume so, although it's closer to a better Java, than a better C++ for this.

Instead it displaced Python for this (not for research/NumPy/Colab stuff), maybe some Java (where it's easier to containerize).

And if it did displace C++, it was in greenfield projects, with non-C++ developers. So it didn't necessarily convert any C++ developers at all.