GOOD OBSERVATION! Vitalik Buterin did build Tag (prolly first implementation of OP_RETURN). Also, in 2013, Vitalik proposed more complex scripting for Bitcoin. He submitted a proposal to the Bitcoin core community. It was rejected—Bitcoin devs prioritized security and conservatism. So Vitalik said: Fine, I’ll build my own chain—with blackjack and DAOs. Ethereum was born in 2015 (it wasn’t until 2017+ that USDT moved to Ethereum, Tron, Solana, etc.) :)