@Edent Has anything changed in the 7 years since you wrote that? How fragile is cryptography really? It obviously needs to be quantum-proof. Most other options depend on a single source that could go away. Keybase tried to provide a way to prove identity and ownership, but it's not really taken off.
Like it or not, blockchains can be pretty robust as long as you have enough witnesses/miners/nodes.
I'm sure smart people can come up with something else.