Re: How long can a monopoly survive unregulated?
Google has about 90% of web/mobile searches in Europe. Which, yes, more or less makes them a monopoly.
Owning the "intent" of the consumer is terrifically powerful, which is why they are so insanely valued. There are two big "buts" (no, not that kind):
Facebook owns "identity", which is why they bought Atlas and why they now tout their efficiency above Google's. In other words they serve ads to more of the right people. (yes, there is Google+ and Google Mail, but they are footnotes in the scheme of things compared to 1.6bn FB accounts)
Secondly, a monopoly, even fairly acquired, is a precarious position as any hint of abuse will attract the wrong attention. And here is one area where Europe and the US usefully have a similar stance. So Google can't leverage their advantage because they'll get called out.
So you could say Google is snookered, though that will take a long time to play out.