As for now there is no any substitute for BTC.Etherum value is also increasing but its not considered to be substitute of BTC.As for my knowledge is concerned in coming future There may arise some substitute.But if we study the history of BTC & analyzed in light of that we will conclude that after undergoing many dips it recovered itself and pumped it.Fluctuates several times yet its the favorite of people.It gave the world a new concept of Cryptocurrency.For many years to come there seems to be no replacement of BTC.All the world has turned their eyes to BTC.Currently its value is under dip and many people think that it would not rise once again.I can say surely that it will pump up and will sustain courage of its investors..
The substitute can be derived in many ways. In terms of usage or price, market cap or acceptability. I believe you are talking about the price here. Yes, in terms of price the substitute of bitcoin is still not found. The second largest cryptocurrency ETH is not even close to bitcoin's price right at this moment. However, that certainly doesn't mean that no substitute will be found in future. I strongly believe that bitcoin will be taken over by another coin within due course of time. That can be ETH or can be something else as well.