Let’s face it: PoW algorithm lead the Bitcoin currency to nowhere. If someday Bitcoin become to be no. 1 world reserve currency the price of it would raise to over 1 million dollar for unit. This price on 2021 means electricity waste of 1 bn dollar daily on PoW mining. Same price on 2019 means electricity waste of 2 bn dollar daily. It is obvious that those quantities of energy waste are not substantial.

As the Bitcoin system work on PoW, the miners community grab all the bitcoin community on the balls. They would never agree to give up their huge income from PoW mining, even if they’ll be shown that other authentication algorithm will be better to the bitcoin community and to Bitcoin as a system.

Future hard fork in the Bitcoin network is inevitable. Otherwise, Bitcoin will lose its consensus as the main cryptographic currency to another no-PoW currency. The losers from such developement would be all the bitcoin community: investors, users, merchants, and Bitcoin services suppliers.

The best solution, by my opinion, is an immediate fork which changes the mining algorithm to DPoS (or any other algorithm that not include huge electricity waste in its core functionality) after block 630,000 (approx. on year 2020) The miners would have relatively low resistance to this kind of update, as their business plans are not go so far, and as their actual mining hardware shall be anyway useless on that future point. Miners that’ll enter to the mining scene with new hardware in the future would anyway take this fork in their rentability calculations.

It is important to code this update in a way which the miners would not know what clients and what users use the forked version, so they couldn’t discriminate them in any way. This point is very easy to implement, as there is no difference between the functionality of the two versions before 2020.

There is no need to wait for a non-PoW algorithm will prove effective over the years. If we will discover in the future that DPoS algorithm does not work properly, or there is a better algorithm, the fork would be updated to the optimal algorithm. Anyway, the fork has no effect on the current functionality of the Bitcoin network, but only on the functionality of its future after 2020.

Meanwhile, leaders in the community, as exchanges, blogs and wallets developers will inform the users about the proposed change and its meaning, so when the inevitable hard fork in the blockchain will happens, all the Bitcoin community will be behind the more efficient forked version, leaving only the miners with the old one.

The core developers will be able to take further action to prevent "miners rebellion" before the year 2020: the threat that if such a revolt happens, transition to the new non-PoW algorithm will start immediately. Not in the future, so the miners will lose their expected income till 2020.