[atweiden]

> In either case you can use your accumulating capital to accumulate more capital -- PoW just means consuming actual resources to do so, as you fold your earnings into more hardware and electricity to earn more.

Proof-of-Work miners have ongoing variable expenses to contend with — electricity cost being the major one.

Conversely, in “Proof-of-Stake”, mining is virtually costless, because it's enough to show you have money to then earn money with your money.

(Disclosure: I’m invested in a true hybrid PoW/PoS system, so I’m familiar with the downsides of both.)