Additionaly. Let's recollect why Bitcoin, blockchain were invented? Blockchain exists to prevent things like arbitrary money supply changing, arbitrary accounts freezing and seizures. ETH did exactly what blockchain is supposed to prevent people from doing. Of course the original chain survived (that's by design, original chain survives as long as it has at least few supporters), but it has much less support than the fucked chain, what questions the very sense of cryptocurrencies existence.
So ETH in essence is already a fiat currency, but it has appearance of a crypto. Nonetheless sooner or later it's gist will become more evident.
Let's ask ourselves what changes if ETH switches from blockchain to a PostgreSQL database hosted by Ethereum Foundation? Smartcontracts will be easier to develop, no need to run heavyweight fullnodes. Almost any hack can be easily reverted. Everything will become easier, better than it's now, except one thing: ETH would loose appearance of a crypto.