Isn't this what Tim Berners-Lee's Solid Project is trying to solve? It's an interesting nut to crack.
I can't see how I could ever get the interesting/profitable/problematic data (my location history, my neighbor's doorbell videos of me, call records, purchase history at Target, and which ads I click on) into something like that.
Beginning with your own data and metadata is very different than data about you.
Sure, ̶b̶a̶n̶k̶ ̶r̶o̶b̶b̶e̶r̶i̶e̶s̶ ̶a̶n̶d̶ ̶u̶n̶d̶e̶t̶e̶c̶t̶e̶d̶ ̶f̶r̶a̶u̶d̶ Identity Theft is a Bad Thing, and this would seemingly minimize the number of SQL dumps my birthday and SSN appears in, but that isn't exactly The Data that Big Tech feeds off of.
Where that data is content and the interactions themselves, it's also different.