The value that people place on Bitcoin (and I don't mean the economic value) is much higher than what Ethereum can get. Ethereum can continue to grow, there should be no problem, but it will never be as "important" as Bitcoin, so I believe that Ethereum will never surpass Bitcoin, neither in economic value nor in any other way. A very significant fact (I read about it in an article a few months ago) is that investors when they must sell, they will always sell Ethereum before Bitcoin, feelings about it play a fundamental role.