What do you mean by this, exactly? Bitcoin miners look more than willing to earn money on brute forcing hard problems.
The point of proof-of-work is that it shouldn’t matter what anyone thinks about it. It’s basically impossible to ban (anyone can do a SHA256 calculation), and the difficulty automatically adjusts. In addition to this, the block reward — currently 12.5 BTC per block — halves every ~4 years, so less and less electricity will be consumed until only transaction fees provide capital for proof-of-work[1].
[1] http://www.bitcoinnotbombs.com/wp-content/uploads/2014/06/37...