Because the rest of them watched and learned from Microsoft's mistake. When the antitrust campaign started, Microsoft was giving a paltry $10K to political campaigns. By the time it ended, they were giving $1M a year to BOTH sides, and wound up with a hand-slap. The rest have cozied up to the federal government since the start, and have no fear of antitrust efforts. What they really need now is to be categorized as public services so that they can enjoy some of that sweet, sweet regulatory capture that Verizon, AT&T, and Comcast benefit from.