Laws and law enforcement. We should demand our governments to make laws that make unauthorized (by the people themselves through a decentralized system) use of our data illegal. At least the more flagrant/large scale forms of abuse could be prevented that way.
Exactly – this is currently a regulatory problem, and blockchains, decentralized identity, etc. won't solve anything in this space. On the contrary, it will by definition enable identification in some types of data.
This makes me conclude that these types of solutions are really more about portability and making some sort of political point (the only thing users realistically control is first party authorization – nothing else); They certainly don't have any security or privacy-related guarantees.
