Your assumption of his naiveté is quite charitable. Before becoming the mouthpiece/patsy for ETH he was doing a quantum computing scam. He claimed he was going to compute NP problems in P time by simulating a quantum computer in software. Absolute hogwash obviously
https://davidgerard.co.uk/blockchain/buterins-quantum-quest/
A more cogent explanation is that Vitalik finally found the right way to pull a con.