Why doesn't proof-of-work allow passive compounding of rewards?

In proof-of-work, maintaining influence requires ongoing real-world expenditure on hardware and electricity — there is no passive compounding. Unlike proof-of-stake where rewards grow automatically in proportion to holdings, proof-of-work participants must continuously compete, spending real resources each round they want to earn. This means a miner's share of the network is not self-reinforcing: to stay influential, they must keep investing time and money. For beginners, this is the key structural difference: proof-of-work ties ongoing influence to ongoing cost rather than to how much you already hold.