Counterpoint: Proof of work requires a miner to select *one* branch of a blockchain to dedicate his hardware to. So counterfeit branches will always be ignored by the majority of miners. Proof of stake allows miners to back as many branches as they like, since they'll have a stake in all of them. Also, the energy consumption of POW is massively overstated. I've seen articles saying crap like "each bitcoin transaction costs the equivalent of a month's electricity for an average household." Unless bitcoin miners are kind minded philanthropists making hundreds of thousands of dollars in losses per block, those kind of statements just don't make any sense.