I worked as a developer at software companies for nearly 40 years. I saw that the most common practice was to promote the strongest technical person to management. It was almost always a mistake (including my own stint as a manager). You lost the best developer and gained the worst manager. In fact I have always joked that the weakest technical person should be promoted. The skills that make a good manager are completely different and the personality needed to be a good manager are often not found in highly technical people. I am completely convinced that Google is right about this whatever other failings they have in their culture.