Well, it’s certainly not evidence against, but it’s still possible that there are n-families of unrelated grammar structures and Google’s training caught enough

Well, it’s certainly not evidence against, but it’s still possible that there are n-families of unrelated grammar structures and Google’s training caught enough examples of each of those families via popular languages. Also, for all we know, they failed on a bunch of languages (unless there’s a paper somewhere I missed, but sadly the days of good AI papers from for-profits seems to be over).