The billion dollar question is how we can have completely decentralised (and not merely distributed) consensus without proof of work. It's a difficult question,

The billion dollar question is how we can have completely decentralised (and not merely distributed) consensus without proof of work. It's a difficult question, and various proposals like Proof of Stake (not secure) and Consensus Ledger (not secure, not decentralised) have all failed technically and on the market.