Theoretically, it is possible. But the thing is that bitcoins are limited in number. Hence, you can consider bitcoin as very valuable and rare. For this, it is impossible for ethereum to surpass bitcoin's price. As when people will see bitcoins price declining, they will instantly buy as many bitcoins as they can, hence increasing that demand to accumulate the bitcoin. Ethereum surely has the quality to become a big crypto currency, but I highly doubt that it will cross the bitcoins.