Many other projects are using ethereum and are based on ethereum so this makes eth one of the strongest coin in the world. It deserves the title of ICO king.
A lot of teams have linked their projects with the Ethereum platform, this makes it so attractive even now when its price has fallen very low. However, Ethereum owes its popularity to the ICO and it gained it quickly enough. I hope in the future we will see at least a few alternatives with the same level of popularity and demand.