01 · The problem
Proof of work ended up with a few pools.
A small miner who mines alone waits weeks for a block, so they join a pool. The pool evens out the luck — and in exchange it holds their payouts, takes a fee, picks the transactions and casts their vote.
Thousands of miners, a handful of operators. Every one of them is a single point that can be hacked, pressured or simply disappear with the balance.