Decentralization will happen on its own once there is no 'center of power' that can hold the mega-whatevers together. Adam Smith told us about this: it is the immense power of millions of people coordinated only by the feedback resulting from acting in their own self interests. Read Leonard Read's essay "I, Pencil" if you haven't. A lot shorter than "The Wealth of Nations" but hits the nail right on the head. https://fee.org/resources/i-pencil/