Vitalik is not the only dev on ethereum. There are over 70. Vitalik has created the idea and whitepaper already.
yeah but the market wont care about that, it is all based on FUD, hype and perception. Mike Hearn wasn't even a real core developer and his tantrum dropped bitcoin 20%.
If Vitalik disappears ethereum would crash, there's way too much hype centralising it around one poor kid who's way out of his depth ... it's kind of sad how they are exploiting him.