I don't think government intervention will change anything. There will always be some government somewhere that won't restrict PoW mining.
4 years after the OP, we're still at the same point. The problem has maybe gained a wider awareness, but solutions are either not very popular (PPC, NXT...) or need yet to be proven (Ethereum's Casper PoS, Cardano's Ouroboros PoS)
edit: there's not only PoS solutions. IOTA could be an ecological alternative too.
Let's say that PPC has equal security, etc, to bitcoin, that both of them have the same transaction fees, and PPC uses dramatically lower energy consumption. What would cause a shift to PPC? It seems to me that there is no economic incentive for anyone to switch from bitcoin, now and in the near future.