Well, maybe I'm in the minority - but when I'm not happy with something I pay for, I make damn sure it gets changed. It takes a bit of effort - and usually involves a bit of time, but it works.
What can we do with a company like Facebook or Google when we're no longer happy?
We can stop using it, and create or support alternatives.
We're used to the cost of a service being its monetary price, or more recently, the demands it makes on our attention. Perhaps a new type of model is being developed in which the price of a service we desire is not in the form of money or attention, but our data. And in this case the way a company uses our data is a real "cost", rather than a mutually beneficial outcome.
I think that threatening to withdraw and withdrawing payment, whether monetary or otherwise, will prove to be a significant balance on the actions of companies. If the changes are significantly detrimental, consumers will take the actions they consider necessary to address those concerns.
However, I think this idea presents a false dichotomy. We need other options which don't involve either remaining compliant or quitting.
While we're told we have freedom, because we can exit - we end up investing so much in a service, that quitting becomes very 'expensive' (in terms of human cost). Quitting becomes a unrealistic option for most.
I think the same can be said for Apple's POV re. the iPhone and competition. They like to say that users are free - and that if they're not happy with the way they do business (or change their terms) then they can go elsewhere.
In reality, users have spent a large amount money on their hardware - and are usually locked into 18-24 month phone contracts. The arguments are disingenuous.
What can we do with a company like Facebook or Google when we're no longer happy?