You think? Bitcoin is certainly here to stay, not matter what happens. However, it is more likely that bitcoin will be used as store of value while Eth will be mainstream from looking at active chain development towards performance enhancement.
Bitcoin and Ethereum have gone so far since they have passed all the tests of time. There are already huge businesses that are starting to adopt and accept cryptocurrency. I believe that it would have a huge part on the growth of crypto. Ethereum could rise when the price of Bitcoin rises as well. There are even huge merchants who are planning to accept cryptocurrency so I'm sure that Bitcoin and Ethereum could possibly grow and rise continuously. We only need more adoptions.
I agree but do you think that we will be able to spend bitcoins as we use fiat? Count buying a fevistick glue from a superstore or let it be a pair of kids shoes. Now think of them buying with Ethereum (or ERC20 tokens).