What do you think? Is the endgame for ETH approaching? Will it be possible for ETH to become decentralized again? Or is it already too late?
I think it is already too late, they have taken a decision that i can't see them going back on. Ethereum will remain centralized and there is little to no chance of them returning to POW or becoming decentralized again. Big centralized exchanges like Binance and Coinbase, and also Lido which is staking protocol somewhat control the Ethereum blockchain because they are the biggest node validators by a long mile.
I don't think we must to bet anything because Ethereum suffered fud in the past about Vitalik's death.
The OP never said Vitalik is dead, they are only talking of the influence which he has over Ethereum project, and if the project will continue smoothly if he is no more, i think it will be very difficult for Ethereum to progress without Vitalik; another person will take over, but so many people will lose interest in the project and prolly sell off their ETH.