the argument is simple :
where does the energy come from?
if Bob has 1000 Bitcoin and wants more how does Bob get them?
lets look:
- Bob buys them. (Bob expended energy in the form of paper money or good or services)
- Bob Trades them for profit. (Bob just transfered someone else's energy and made a profit, someone else lost this time)
- Bob Buys hardware and mines them (Bob expends either Bitcoin (energy tokens) or fiat (energy tokens) and buys hardware and mines them)
or
Proof of stake says Bob gets "interest" on owning something, this breaks the law of energy equilibrium and transfers energy to Bob.
Ok, I sort of get your chain of reasoning but I think it is faulty. Its not so much about where the purchasing power came from, but to me rather how it is spent. For example dollar bills can be literally burned. That is a form of useless spending. Or dollar bills can be used to buy bitcoins. That is better in my opinion, regardless of how much coal was consumed to create those dollars in the first place. And that is all I have to say on this until the code to be written can speak for itself.