Or we could all switch to Ethereum, which will have Proof of Stake (low electricity costs) instead of Proof of Work (insanely high electricity costs) mining soon.
We could all switch to proof-of-stake, but then anyone would be able to create a valid-looking blockchain in a few minutes, and the only way to get the right chain would be to connect to nodes you know or trust, at which point a blockchain becomes meaningless in the first place.
The challenge is about coming to agreement. Reaching agreement on information which determines how much money people own is hard. Proof-of-work reaches consensus by having a vote -- on which transaction history is correct -- constitute something that cannot be forged: energy.