Do We Need Government Intervention in the Form of Competition Policy?

Competition policy aims to ensure, wider consumer choice, technological innovation and effective price competition. If achieved, the above aims contribute to both consumer welfare and to the competitiveness of the industry. The main thrust of competition policy is to ensure that, companies compete rather than collude, dominant companies do not abuse their market power, and efficiencies are passed on to final consumer in the firm of lower prices and better products.
In the real economy, is it always necessary for government intervention in the form of Competition Policy?
Let's consider The United States Airline Deregulation 1978.
This deregulation is seen to be successful, it brought benefit to customers. However, it also raised some problems such as congestion, limited re-emergence of monopoly power and with it, and the exploitation of a minority of customers. So when do we need competition policy?
Abuse of market power is best tackled through antitrust policy. Externalities can be reduced through regulation, a tax or subsidy, or by using property rights to force the market to take into account the welfare of all who are affected by an economic activity.
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