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.
It can be ascertained that ethereum is difficult to surpass bitcoin, even though they are both on the blockchain because they have their respective functions, and are on their way, by looking at both cryptos there is a risk of fluctuating depending on the time to see the situation.
It's not the main point of either BTC or ETH to be above each other or other coins, so you are right - both have their pros and it's alright, no matter what, two are the big coins out there to be utilized by their appropriate communities.