if we allow that this combination of market power (search + ads + channels of distribution like youtube, android) wld lead to mass surveillance, what prevents other companies from arising and abusing this power? Other countries would hv to go along. I don't think trading Google dominance outside the US for Baidu solves anything.

I guess if google went full evil they'd have enough blackmail material to take down just about anybody at this point including politicians. The backlash if they were caught would be huge, but honestly what would we do about it? Switch to Bing who is just hoping to get enough data on us to do the same (and leveraging data collected from our own PCs to do it)?

They only way I can think of to solve this would be to limit the amount of data that companies are allowed to collect, but can we expect the government to vote for that until google does start to abuse what they have on us? Right now they can take that data and benefit from it as well.