Solutions so far seem to boil down to either "trust other people" (multisignature wallets) or "trust your devices" (a la Keybase: https://keybase.io/blog/keybase-new-key-model ).

Any recovery method can be built. Maybe your bank's key can authorize a new key for you. Maybe your government can. Maybe three out of five friends you picked can.

It's better to start from the other side of the problem: how do you want to recover your identity?