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.