Erick Schonfeld gets it right. The market will always do a better job undermining monopolies than the Justice Dept will.
Watch Out Google, Obama’s Antitrust Chief Is Looking To Make An Example Out Of You
The only kind of monopoly to be feared is one imposed with the help of government favoritism and other sorts of interference in the free market, or operated by the government itself (e.g., U.S. Postal Service).
A Politically Incorrect Guide to Antitrust Policy - D.T. Armentano - Mises Institute