In the case of Vitalik, he was smart enough to enlist people more knowledgeable than him when organizing the Ethereum project. For example, he enlisted a PhD, Dr. Gavin Wood, to author the real white paper[0] (also known as the yellow paper). while it's possible that at 19 Vitalik could've been studying real CS long enough to work out the truely difficult parts of implementing his vision, it's highly unlikely and, to his credit, he was smart enough to know that. People who think they are the smartest people in the room rarely are. The really smart ones are the ones who realize this and are humble enough to seek the expertise of others.
[0]:https://bravenewcoin.com/assets/Whitepapers/Ethereum-A-Secur...