Proof-of-Work is the oldest proof-concept known to be used in cryptocurrencies' scalable ledgers. It was essential back in the days - to define the bitcoins price with some "effort" that had to be putted into Bitcoin mining (hardware + electricity) and for the security purposes with the idea in mind that each miner that is participating in the mining process is also a part of the network that is secured by it's hashing power. To date Bitcoin mining is a huge, competitive business with many big companies involved that use incredible amount of hardware and electricity to produce brand new Bitcoins and secure blockchain's network. It achieved the stage when the power drains attract more and more people outside the community that see this fact as an issue - there are plenty of complaints on the social media about the huge power wasting that also have negative impact on nature and moreover - that is "surely" not necesarry for production of such a small amount of Bitcoins.
The problem that Bitcoin is facing here is that with PoW it discourages the potential new users that might join the network. Those are probably the common people with environmental priorities on their mind.. The fact is however - these common people also do not know some of the aspects of PoW that play crucial role in how Bitcoin's network work and that might also be a reason for them to complain:
1. - Bitcoin mining is a comeptitive discipline that anyone can join and thus bring even more electricity consuption into the game, so the community that has been around for almost a decade cannot be judged for doing it's job while other, newer competitors appear.
2. - Another thing that common people probably do not know is the fact that miners also fortify the netwok to make it secure from DDoS attacks and other kind of potential cyber threads and as the Bitcoin community broadens it's horizons it is absolutely necessary to keep the network safe.
3. There are many other coins out there that are running Proof-of-Work and also can be mined - of course the amount of electricity used for that is not as huge as in case of Bitcoin but still - it is not fair to put all the blame on Bitcoin. Ethereum for instance is the 2nd cryptocurrency with the huge support of amateur miners that are mining with their GPU rigs from their houses thus also participating in the power consumption exchanged for production of new coins.
Ethereum however is planning on switching to PoS (Proof-of-Stake) system in the near future. What about Bitcoin and the PoS switch?
Home made miners that anyone can build
huge Ethereum mining facilities also exist
Bitcoin's PoS (or any other proof-of-something system except the PoW) switch has not been discussed yet and chances are - it will never be discussed. At the moment Bitcoin's priority #1 is to solve the scaling debate that has been around for whole 3 years and only now it looks like it is going to come to a certain solution. Probably the next thing that is going to be the topic of Bitcoin's protocol discussion is the implementation of Smart Contracts that are seriously demanded from the corporations that are utlizing Bitcoin's blockchain to run their proejcts. These are the number one reason why some of the companies switch to Ethereum blockchain that has the Smart Contracts technology implemented since the day one. Thanks to upcoming SegWit activation the further Bitcoin's protocol upgrades won't be such a long lasting pain in arse making the idea of Smart Contracts implementation seem not so scary or complicated for developers and the network. Still though - we are talking about years until the network is ready to undergo any further upgrades. And because PoS is whole new concept that completely changes how the scalable ledger is distributed, it sounds pretty obvius that even though it is possible that PoS might be be mentioned as a possible solution to power drains but it won't be seriously considered as the idea for Bitcoin's protocol upgrade any time soon.
So for now even though there are numerous complaints about huge power wasting (and there will be even more of them in the future) it is far the last concern of Bitcoins community and it's developers - there are more demanding problems to be solved and that makes electricity waste problem simply not to have the priority for now.