Politically, this framework is at the root of the problem. Currently, privacy violation is only policed based on method of access, rather than a larger general concept. We put "hackers" in prison for years for "breaking into an email account" because they shared a few people's private information, yet commercial surveillance bureaus are free to do whatever they want because the data is already "out there". Focusing solely on access kills any independent concept of privacy.
Specifying what exactly should be considered wrong is obviously a challenge. I think a business entity having someone's identifying information in a database without an ongoing business relationship could be a decent first pass. This difficulty is a large part of what has stunted progress. (Just FWIW my usual assumption is that information dissemination can't be stopped, but I don't think that assumption is necessarily true when talking about policing commercial entities that inherently have government charters.)
I'm actually more hopeful for technical solutions to the problem, even though they suffer from problems of scope, implementation, financing, and adoption. But coming up with a better external concept of privacy can guide such things too, especially encouraging incremental change in business models as opposed to the moon shot of repaving it all with Free software.
And when will it be useful? The scariest thing is when all this data will be used by smart algorithms designed to construct plausible stories in a court of law about you, making anyone a target for legal threats and jailtime and intimidation. It's already the case in more totalitarian countries, but this is about free countries where juries of peers and other systems will be subverted with clever algorithms and a mountain of data to use.
All your blockchain and anonymous transactions are stored until such time as you slip up and get deanonymized.
All you are currently relying on -- all that our legal systems are relying on -- is inefficiency of the attacker. You think they can't cross reference enough materials, analyze them deep enough, at a large enough scale, fast enough, and can't put two and two together. But the growing repository of data is there to be (quantum-cracked and) mined for information.
Ask yourself this: what would it take for a determined attacker to ruin your reputation or credit today using only the techniques in the NSA field manual? https://theintercept.com/2014/02/24/jtrig-manipulation/