I also work at Google and I agree with the general sentiment that AI completion is not doing engineering per se, simply because writing code is just a small part of engineering.
However in my experience the system is much more powerful than you described. Maybe this is because I'm mostly writing C++ for which there is a much bigger training corpus than JavaScript.
One thing the system is already pretty good at is writing entire short functions from a comment. The trick is not to write:
function getAc...
But instead:
// This function smargls the bleurgh
// by flooming the trux.
function getAc...
This way the completion goes much farther and the quality improves a lot. Essentially, use comments as the prompt to generate large chunks of code, instead of giving minimum context to the system, which limits it to single line completion.