“Nakamoto's genius, then, wasn't any of the individual components of bitcoin, but rather the intricate way in which they fit together to breathe life into the system. The timestamping and Byzantine agreement researchers didn't hit upon the idea of incentivizing nodes to be honest, nor, until 2005, of using proof of work to do away with identities.
Conversely, the authors of hashcash, b-money, and bit gold didn't incorporate the idea of a consensus algorithm to prevent double spending. In bitcoin, a secure ledger is necessary to prevent double spending and thus ensure that the currency has value.
A valuable currency is necessary to reward miners. In turn, strength of mining power is necessary to secure the ledger. Without it, an adversary could amass more than 50 percent of the global mining power and thereby be able to generate blocks faster than the rest of the network, double-spend transactions, and effectively rewrite history, overrunning the system. Thus, bitcoin is bootstrapped, with a circular dependence among these three components.
Nakamoto's challenge was not just the design, but also convincing the initial community of users and miners to take a leap together into the unknown—back when a pizza cost 10,000 bitcoins and the network's mining power was less than a trillionth of what it is today.”