And how would breaking them up prevent any of that? Facebook doesn't have a monopoly on data collection, Google doesn't have a monopoly on display advertising, and Facebook doesn't have a monopoly on peer pressure.
The value and impact on commercialized surveillance depend critically on the ability to generate large databases, both on the any specific indivual, and on the the number of individuals thus affected. Breaking up dataminers probably would help.
And if we take a step back: this isn't necessarily only about privacy, but about capitalism and competition. Data-miner customers, and data-miner subjects might both get a better deal if there were competition between the middle men, at least more than now.
They have monopolies on the political leverage that comes with all of the above.
Verizon and Comcast could play the same game, but they're still more about money than influence - which is why they've chosen to make their stand on killing net neutrality, not on influencing referendums and elections.
FB particularly is incredibly toxic to genuine democracy - not necessarily more toxic than some of the other monsters in the mainstream media shark tank, but certainly not a company that should be allowed to run riot without oversight.
And if we take a step back: this isn't necessarily only about privacy, but about capitalism and competition. Data-miner customers, and data-miner subjects might both get a better deal if there were competition between the middle men, at least more than now.