Most of it has to due with lack of education about what it takes to secure a PoW blockchain and why you would want to. I think basic laws of conservation and thermodynamics will point the way forward. Miner swarms will be placed in LEO's and will be powered via solar energy. Ground based farms will also be powered via microwave transmissions sent from the orbital solar arrays. It will take awhile..but we will get there.


*edit*

https://youtu.be/lp5Yx34SO58?t=19m28s