I know tying a UID to yourself and keeping your data in a central repository isn't the most welcome solution, but at the moment your identifiable attributes are fragmented across a vast ecosystem and not at all in your control. A data compensation mechanism seems a natural extension to the 'data donation' schemes that are currently gaining traction in academic circles -- some users are more inclined to share fitness data while others have less issue with sharing their social media history for analytical purposes.
No doubt this would still result in a less private public overall, but the end-user can at least take back (some) agency in how data is put to use while making some passive income on the side.