These companies aren't a challenge to government power in the US, on the contrary they are a powerful tool for social control. The relationship between massive corporate cartels and the US government has become so incestuous that a distinction can hardly be made, it's just a question of faction in-fighting at this point. The centralization/monopolization of the tech industry makes it more convenient to conduct mass surveillance, as evidenced by PRISM. Its safe to infer at this point that all major tech companies in the US are already infested with alphabet spooks, there's no incentive to break them up as far as the feds (that actually matter) are concerned. Just partisan barking with no bite for the sake of 'optics'.