“At the core of Epstein’s analysis is his identification of conditions under which so-called ‘big tech’ firms might be prevented by the common law from deplatforming, or refusing to platform, customers. Specifically, the law sometimes holds that firms that are monopolists have obligations to the public that are more extensive than those firms would have were they not monopolists.
“And so if companies such as Twitter and Facebook have monopoly power, they are subject to the Anglo-American common-law rule that (as described by Epstein) ‘no private monopoly has the right to turn away customers.’ Such monopolists must serve all customers on terms that are ‘fair, reasonable and nondiscriminatory.’ A useful acronym for this requirement is ‘FRAND.'”
Epstein appears to say that the common good justifies government regulation of a monopolist enterprise, but I don’t think that’s what he means.
A different way to read his argument is to note simply that the common law provides a safety valve for disputes involving monopolist behavior. Because the safety valve exists, such disputes can be resolved by adjudication, short of violence or vigilantism.
In other words, FRAND allows the rule of law to prevail by giving disputants something to focus their conflicting claims upon.
Ultimately, however, no monopoly is perfect or capable of infinite extension. None is wholly immune from either competition or entropy.
Thus, the back side of Epstein’s argument is that it shouldn’t be necessary to forcibly break up monopolies — because lesser remedies exist.