It is of course not 100% perfect analogy, nothing is, but I believe you understood the point I tried to get across: it's a security service, and that costs money. Blackwater stationary guard roles are 180-220k a year for someone with years of experience. I'd imagine monetary networks use a lot of physical security, some central banks are literally located in bunkers under mountains, with a backup site in a similar setup on a different geological plate.
I have not seen any PoS schemes so far that provide anything other than plutocracy as a service. There is a reason why ETH with a 100mil R&D budget is still on PoW, Vitalik is not a dummy.
as for the cheap sources of sustainable energy, those are usually stranded hydro and wind that's too remote to be economic, and stranded natgas (for natgas "green" might be a better term, i've used sustainable in the sense that CH4 is far more damaging that CO2. I've been told by regulators it is actually better to burn off CH4 from stranded wells)
Balancing of the grid also does happen, but I believe primarily with wind and hydro.
I, of course, agree that we should not pollute the Earth we live on. High energy usage in itself is not bad, only if it's a harmful polluter. I've only pointed out dishwashers and pools (don't have the stats handy, but they do indeed use a lot more, like a magnitude more), as a common hypocrisy.
We must rapidly scale up non-polluting energy sources, as it seems unlikely humanity can become a spacefaring species on a self-imposed tight energy budget, and this self-imposed handicap coupled with an unexpected asteroid impact can end us.
