Ethereum won't surprass Bitcoin because it is worse when it comes to scaling. Currently, the whole transaction history of Ethereum is way bigger than Bitcoin's which causes a lot of problems. People don't synchronize their nodes fully which means that Ethereum network might become less secure over time. Bitcoin will continue to be number one thanks to Lightning Network.
But in ethereum in the coming months, we need to implement the Plasma project, which should solve all problems with the scaling of this coin and it will allow it to have hundreds of thousands of transactions per second instead of the current fifteen. The truth is that this will not give ethereum an opportunity to bypass bitcoin in the short term.