Proof of Work vs. Proof of Stake
Blockchain is built on the principle of equality. It is a peer-to-peer system or agents with equivalent authority. If some agents in the system cease to exist, blockchain will continue to operate because of its decentralized nature. Peer-to-peer means sharing your personal resources with the network: disk storage, GPU/CPU power, RAM, network bandwidth, etc. This process consumes energy and therefore requires investment, reliability, and responsibility from agents in the network. For blockchain, such agents are miners and nodes.