It's easy to create data that can't easily be destroyed. Back it up. You don't need a cryptographic, anonymous data mutation algorithm to do that. Just copy it to more places.

And as far as not having one gatekeeper... none of those things have one gatekeeper anyway. Who is lamenting that there's a single gatekeeper for their health history? If anything, people are lamenting the opposite -- that it's such a mess where multiple people have to cobble it together from disparate records formats.

To paraphrase something once said about JavaScript: the useful aspects of blockchain aren't new, and the new aspects aren't useful. Immutable (aka append-only), distributed, encrypted databases are useful! They are not blockchains, though.