I understand that it's not a pure meritocracy story and an element of timing was involved. But I was scrolling to find some description of what was accomplishe

I understand that it's not a pure meritocracy story and an element of timing was involved. But I was scrolling to find some description of what was accomplished in each of the steps. In many big companies there is an inherent motivation to replace the old with new to get ahead without improving the state of the art.