Yes, it's co-dependency; it's also a convenience for me without being much of a privacy risk because the search engine, indexes and content all sit on my own machines, not on those of someone who can make money selling information on my habits to marketers.
That's the problem Google runs into with anything it does.
Its real genius is in finding things quickly. It constantly gets into trouble by finding things other people don't want it to find.
In China it got in trouble for finding things the government didn't want it to find.
In Europe and the U.S. it got into trouble for finding information on individuals demanded by various governments (it would have gotten into worse trouble for not doing those things, but when your specialty is finding information other people think is lost, there is a strong J. Edgar Hoover angle you can play in those situations).
When you run social networks, email networks, chat, picture and file storage services, users expect you to be a little circumspect.
Sure it's easier to be able to search everything at the same time from the same place.
That doesn't mean it's a good thing to put them all in one place where they can all be searched – especially if you plan to cull that information for data that's valuable to people or companies that would dearly like to exploit your customers' habits for their own profit.
It doesn't mean your customers will be happy to let you combine information on all their activities from all your services into one place specifically to sell to advertisers, even if you tell them ahead of time that you're doing it.
It just rubs salt in the wound that the customers whose little remaining privacy Google plans to erode even further are those most dedicated to it and its various services.
Yes, Google can track the habits of anonymous users with cookies and other techniques.
The real profit is in tracking in great detail the habits of its account-owning users – the ones who have to sign in before they use the service, rather than those who just browse through it.
Opt-out is possible, but not easy
It's not true that Google won't give those customers the opportunity to opt out of the tracking service.
It doesn't make opting out easy, however.