I think you are hinting at a very important aspect of the cryptocurrency space; namely, with consensus algorithm is best with blockchains? It is quite obvious that PoW is very wasteful, but certainly a reliable form for securing the network. POS and DPOS alleviate the waste for consumption of electricity. It would be interesting to see if these systems can be co-opted by bad actors or oligopolies. Seems the steem is doing well so far. I believe there should be more research into alternative systems to consensus so that actual experimentation in real-world networks can determine winner(s).