I understand your point. But we may have different terms for "owning data". For example, you can own a house but everyone can look at it but you can decide who can enter it.
Imagine in the future data storage that keeps track of insulin levels of a diabetic every 5 minutes. This data should be owned by you, the data could be shared with necessary third parties, but owning it and deciding what to do with it should be your choice.
> the data could be shared with necessary third parties
Correct, in the status-quo it already is.
> but owning it and deciding what to do with it should be your choice.
Remind me again why we need Blockchains to provide this?
I'm not going to rip into your example, but I think it's a perfect idea of how far I need to suspend disbelief to see a practical crypto implementation. People have lost the script entirely and just think crypto is a trustless database, and we need to pivot away from this currency thing to target a market that crypto will always be disadvantaged in. There is no practical reason to store my health data in a public blockchain. It is a security liability even if encrypted, merely because another copy of my personal info exists.
Even assuming you make it to market with an open-source blockchain with zero fees, maintainers from God himself and hourly airdrops, you'll just get poached by someone who can do this faster, easier and cheaper on a single database. Darwin eats socially-conscious startups for breakfast.
private data is "private" in the sense that it's about you in ways that shouldnt be public, but it's not data that you own
credit data is held by credit reference companies about you, but cannot be actually held by you; that defeats the point
likewise medical recourds are held by hospitals about you, because they need them to provide their service, but cannot be plausibly held by you
what if you're seriously ill and people need access to your medical records?
this doesnt make any sense. The people who create medical records, credit records, etc. are other people, and they create them about you
These people typically have a professionally duty to own that data.