If that information is useless to us, it's due to inadequate tools: software, hardware, algorithms, and philosophy. Facebook and Google are both able to extract value from an individual's information (even isolated) because they have both the software and incentive. Both can look at word frequencies and activity over time to develop behavioral prediction models that are then used to target ads at you.
I'd say the ability to make relevant predictions is a form of power.
Why is it a forgone impossibility for an individual to possess tools to capture similar value from their own information? Does self-knowledge hold no value? In my experience, changes in behavior (such as to better align with your own goals/interests) are often triggered by a clear and quantified message from a trusted source. Why not make this source your own information and your own computer?
Sure, what Facebook has is lower quality and harder to process than we might prefer, but there's nothing stopping us from collecting and structuring our own information in more appropriate ways, then layering on interfaces and algorithms, and then simply doing better than anyone else can. Because it's ours.
So the We is We hackers, who can design and build new information-contexts with different value propositions and power dynamics. And it's also We thinkers who can put together the reasoning behind such efforts. And We as regular people, who want more joy and less pain, with less effort.