Just exactly how do a series of market driven consumer decisions lead to a public platform? Republics like the United States and most other liberal democracies

Just exactly how do a series of market driven consumer decisions lead to a public platform? Republics like the United States and most other liberal democracies are founded on social contracts that have never been dictated by the kind of corporatism that you're describing and in fact have always rallied against it. Even the traditionally held conservative commentators like Edmund Burke railed against things like the British East Indies Company and warned against "corporate tyranny". That the State ought to confine itself to what regards the State, or the creatures of the State, namely, the exterior establishment of its religion; its magistracy; its revenue; its military force by sea and land; the corporations that owe their existence to its fiat; in a word, to every thing that is truly and properly public, to the public peace, to the public safety, to the public order, to the public prosperity. What you're failing to recognize is that we've already given companies like Facebook a public platform through our system of corporate legal structures and more obviously though things like network neutrality. Facebook, like any corporation or any faction of private interest, will take as much territory as it is possibly allowed. It is up to external checks from a government "of the people by the people for the people" to regulate and contain these factional interests. Federalist #10 does a much better job with the discussions related to factional interest than I could ever hope to fit in to a comment box, as do the writings of Paine, Jefferson and, I really can't recommend him enough, especially to the economically minded, Edmund Burke. Also, all of the discussion and legal precedent around the anti-trust laws are very pertinent to any discussions of the limits of corporate power. And yes, in case it isn't clear, what I am arguing for is a form of conservatism, but a form not predicated on dogma. Think Chesterton's fence.