PoW and PoS are ended in over-concentration on off-chain hardware and coin hoarding. If you really look out to the future pay attention at cryptocurrency startup TAUcoin. This startup introduced a new Proof-of-Transaction (PoT) consensus mechanism. PoT uses on-chain historical accumulated transaction fee to determine who can propose a new block. In PoT consensus, no advantage is given to accumulating wealth and hardware.  PoT is used massive users' daily economical behavior and transactions to protect network security and grow the blockchain.