I dont think that even if time is given ETH cannot surpass Bitcoin until Bitcoin network dont get problem or hacked. Because the main reason of Bitcoin being mainstream coin is that it is not controlled by anyone and no one is holding a big junk of coin, so that the market cannot be crashed on it. Almost so many miners are running on btc to work properly. But ETH is controlled by developer and holding a big junk of coins which always will be danger if he sold everything and run away. So many time ETH developer has told that he is always ready to put his profit in real world not in crypto world.