In the scheme I described there would be no central authority with special power over the "recoverable account" smart contract. Each user would deploy their own

In the scheme I described there would be no central authority with special power over the "recoverable account" smart contract. Each user would deploy their own fully independent instance and choose who can help them recover the account. Contracts are immutable so the person writing / distributing the code wouldn't have any extra powers the way Google and Facebook do. Obviously this hinges on the contract not being backdoored by its creator to begin with, but collections of free, open source, audited smart contracts for stuff like this already exists. A user would likely use some app / tool to deploy their instance, once deployed it's really simple to verify the deployed code matches the verified open source version.