Proof of work completely replaces the bureaucracy that maintains trust in traditional ledgers..

A bunch of automated nodes, strewn across the globe, and connected via the internet, maintain the network, with the network being able to seamlessly/autonomously manage nodes joining/leaving.

There are no legal contracts that need to be drawn up, filled out and signed for someone to start submitting PoW, or validating and propagating transactions, to the network. There is no HR department. No payroll. Just machines, and a deterministic compensation mechanism, managed by a fault tolerant network of machines.