So far Ethereum has shown its best utility as a platform to create tokens and raise ICOs. There are already thousands of ICOs launched using Ethereum Smart Contracts and millions of dollars raised in ETH. Hence demand for ETH has already grown near to its full potential, that is the reason why we seeing Ethereum moving between $250-400 from last 6 months.
As outlook towards ICOs is changing nowadays and people have started ignoring most of them, I don't think so ETH would have any magical demand rise in coming time. BTC will remain ahead of ETH in coming years too.