Maybe I'm a bit desilusional but I can see Ethereum coming first on cmc in the  future. WHY you ask? We are slowly but surely moving to usd pairs on altcoins ( the single purpose of bitcoin atm  that creates huge demand ). Ethereum on the other hand has many rivals coming but with the transition to Casper and having the first move advantage over the other protocols I can see it still being the highest rated in the years to come.