“In practice the antitrust laws deal more with oligopolies than with pure monopolies.” Is this true?

What will be an ideal response?

This does seem to be true generally. Pure monopolies are rare and those that do exist tend to be “natural monopolies” that are subject to regulation. Another point seems to be that antitrust laws are used today mainly to prevent further concentration of power in already oligopolistic industries. Therefore, the laws are dealing with oligopolies before one of the firms gets a monopoly position. The cases mentioned in the text seem to support this view.