I see ETH and BTC very differently, a lot of speculative money flowing into ETH with in my opinion a lot more risk of plenty of different reasons, while BTC has the position of money and will most likely always have as long as they dont mess themself up. I hold BTC as core position while I hold ETH as a momentum and more speculative play. Can ETH overtake BTC marketcap? Absolute, maybe even likely, But I sleep better having most of my cryptos in BTC.