In America (and most places), law normally lags quite a bit behind the events of the day. Standard Oil destroyed markets unchecked for several decades in the 1800s. No individual or company could withstand their market power. Then the government divided it into dozens of vertically integrated companies, which allowed for a wave of new market entrants, better deals for consumers, and higher standards of living for more people.
We are obviously at that breaking point now with the tech behemoths and their sprawling, impregnable market power. It is time for antitrust action against Facebook and the gang.