I doubt that hiring average talent and training it is best for Google business. They believe that it is better to try hiring only the very best, and do it even if employees do not match a specific position they ostensibly interviewed for (e.g., train for skills or find new positions, but after a very high entry bar).

I think retraining programs primarily help sharp, energetic folks who somehow got into a bad state (useless major, bad school, rough childhood, etc.); maybe even social connections and stability are more important than the skills they end up getting. However, those programs are IMO worthless for folks who lost a stable job and hope that Yet Another Certification Class will put them into a pipeline for a similar one. I am not sure how to help the second type.