If there is not enough competition, the problem is one of two things:

* barriers to entry created by regulatory restrictions

* a naturally monopolistic industry creating a tendency toward monopoly/oligopoly

In the case of the former, the govermment should simply repeal the regulatory restrictions.

In the case of the latter, the government should directly provision a public option, until that public option becomes the de facto monopoly. With blockchain technology, the government could even subsidize the development of public good smart contracts that enable participants to coordinate, without an intermediary, to provide the good/service in question.

I don't see any moral justification for allowing private citizens to build their own successful enterprise, and then seizing control over the enterprise to dictate how it is utilized.

> and then seizing control over the enterprise

That's an exaggeration. For example, we already require companies to serve disabled customers. They can't just choose to refuse service to them. Have we already "seized control" over these companies? I don't think so. Nor would it be the case with this proposal.

>>Have we already "seized control" over these companies?

Yes, the government has. It just allots them quite a bit of liberty over how those companies are managed.

Fundamentally, once the state dictates how the property may be used in private interaction, it has abrogated the right of the nominal owner to their private property.

"where there isn't effective competition"

That's my point. The solution to this problem already exists - antitrust. The government has just chosen to to enforce it.

I don't think it's anti-trust that keeps eg competition between restaurants or shoe manufacturers alive.

It's low-enough barriers to entry.