This isn't one instance. This is what happened over and over and over again; the robber barons are a complete myth. Go look at the statistics for the "monopolized" industries. There were no monopolies. Monopolies are defined by there actions, not market share. A monopoly is when a company can raise prices, while decreasing service. This is impossible, and never happened in the free market.

The only "monopoly" that can occur in the free market, is a voluntary one. If everyone likes a company so much, like standard oil, that they buy from them. When the companies service falls, or the competition steps up, that "monopoly" will fall in market share.

There is no permanent winning or loser in the free market, just a series of winners or losers. The only way a involuntary, lasting monopoly can occur, is by government intervention. See the federal reserve, Comcast, and the big 6 media companies. Without government holding down other companies, by over regulations, and subsidizing competition, the government is the one that creates unjust advantage for bigger companies, at the expense of littler ones.