The market is normally self-regulated. It suffers from one-time failures when economic agents engage in anti-competitive behavior, mainly the abuse of dominant positions in the ordinary markets, or the abuse of markets in the financial markets, sanctioned ex post by the authorities in individual decisions.
But some sectors suffer from structural failures, which prevent them, even without malicious intent of agents, from reaching this mechanism of adjustment of supply and demand. The existence of an economically natural monopoly, for example a transport network, constitutes a structural failure. Another agent will not duplicate once the first network has been built, which prevents competition. An a-competitive regulation, either by nationalization, by a state control or by a control by a regulatory authority, is needed to ensure everyone's access to an essential facility. Also constitutes a market failure asymmetry of information, theorized through the notion of agency that hinders the availability and circulation of exhaustive and reliable information on markets, especially financial markets. This market failure carries with it a systemic risk, against which regulation is definitely built and entrusted to financial regulators and central banks.
In these cases, the implementation of regulations is a reaction of the State not so much by political rejection of the Market, but because the competitive economy is unfit to function. This has nothing to do with the hypothesis that the State is distancing itself from the Market, not because it is structurally flawed in relation to its own model, but because politics wants to impose higher values, expressed By the public service, whose market does not always satisfy the missions.