I a lot of ways this feels to me like Zuckerberg taking back the company after the Sheryl Sandberg years. There is no adult supervision any more and Mark is now unrestrained in living out his geek ideology that says engineering led companies are better and layers of middle management are fundamentally wasted. I have some sympathy for this viewpoint but I think it is all too easy to under estimate how special the whole culture of an organisation needs to be to actually make fully engineering led leadership work. I am not sure you can impose it from top down. But it will be very interesting to see how he goes at it.