Consensus can't add a 22nd million coin. That's the point. The 21 million cap is enforced by nodes running the code, not by a committee voting on what counts as legitimate. You can fork and create Coin22, but every node on the network will ignore you. That's how math beats politics. BIP-110 flips this. It says miners and nodes get to decide what's 'legitimate' data vs. 'spam.' The moment you give humans that power, the protocol stops being neutral. The 21 million limit works because it's code, not consensus about good taste.