At least, Ethereum is not as centralized as Ripple (XRP) is. But that still won't exclude it from being classified as a security by the SEC. Everything will depend how much power is given to the validators on the network. If the ones controlling most of the tokens on the Blockchain are exchanges and centralized service providers, then you can bet the SEC will be on such entities' tails to enforce securities laws. That won't apply to private individuals, though.
We're going to have to see how regulations will be applied to the rapidly-evolving crypto/Blockchain space. If somehow ETH becomes compromised, then we would have no choice but to switch to "Plan B" by using a PoW fork like Ethereum Classic (technically, it's the original version of the ETH blockchain). No one knows what will happen in the future, so we can only hope for the best. Just my thoughts