We can't guess the future. I don't know if anything else is going to surpass ethereum marketcap but I believe that ethereum is going to be always in the top 10 if they continue to improve the network. The technology in this space is always evolving and ethereum needs to keep up the pace to not be left behind. I trust that the team can find the solutions needed to improve the network but it's going to be a big challenge.
If someday Ethereum drops to below the second position and just stay in top 10 on coinmarketcap, such as at the 5th, 8th or 10th position, it means the Ethereum project has been surpassed and somehow outdated network. If it happens, dropping further in lower position in top ten, Ethereum will definitely fall further behind other projects. Nevertheless, I don't see anything supports such terrible position lose like this from Ethereum project. Their team are very productive, energetic, and creative, they always keep developing, upgrading their network and their ecosystem. Together, I see solid reasons that Ethereum will still be a second largest in crypto for coming years.The competition will be fierce in the future. Even if ethereum drops to the 5th place in the crypto marketcap does not mean it will be outdated or anything similar. It just means that other projects also are in more demand. Let's just make an example on something like samsung or facebook coin if they come to be developed. If the demand is higher for those coins/tokens then it's possible to see ethereum drop on it's position but does not mean that people still not want to develop on the ethereum network.
