Google can't collect my information if I don't give it to them. They can't install splitters at major NAPs, demand that Microsoft give them their data on my or use it to prosecute me. If they engaged in a campaign against their users by leaking embarrassing data they would be prosecuted since doing that is illegal. If the government does it there is basically no recourse.
Like I said, the most dangerous forms of power are obtained by manipulating people to surrender it voluntarily. The fact that Google is, at the moment, not nearly as vilified as the US government allows it to grow its particularly dangerous form of power uninterrupted.
The fact that Google cannot force Microsoft into handing over your data is insignificant. Either Microsoft will eventually become a non-power, or both Google and Microsoft (and Facebook and others) will share power as it suits them – just like feudalism.
The fact that Google cannot currently directly use violence or incarceration against you is circumstantial. When the federal government was week, the robber barons commonly used violence against people (the Pinkertons, for example), and the robber barons never had as much power as Google does now (knowledge is power). Weaken government enough, and this, too, may come to pass. But the worst part is that it doesn't have to: in modern Western society, information alone can often be used almost as effectively as physical violence, at a much greater scale and at a lower cost.
With the power and influence Google holds, I'm not entirely sure they will always be so readily prosecuted for their transgressions. I assume that even now they're trying to remove whatever regulations apply to them, and are certainly fighting any future regulation that may inhibit their aggregation of power.
