I don't think you can really compare on to the other in such a way saying people are switching from Litecoin to Etherium. Litecoin is a digital currency while Etherium is not. The only way I would see Etherium dying is if another blockchain that offers what Etherium does comes along and sweeps the market, like maybe Tezos will.

Regarding Etherium I think people and investors may be a bit weary of the fact that Vitalic has so much say over what happens to the project. It sort of throws out the fact that like with Bitcoin, if most people use a certain software than one fork will "win" over the other. In Etherium it is more follow what Vitalik says. His importance for the project was seen when we saw the fake news of his death and ETH saw that flash crash down to $0.10.