Ethereum is popular now but it is not direct competitor of bitcoin. Their purpose is slightly different. I've seen many 'bitcoin killer' alts in the past and none of them survived enough.
Someone could say that Litecoin is technologically better than Bitcoin - so why it is not more popular or priced higher?
I agree. Ethereum with smart contracts is different than BTC and it will not be a "bitcoin killer".
With smart contracts, it is more useful than the bitcoin. It can be a currency as well as a fuel for the smart contract system.