What most people can't seem to understand is that Ethereum was never meant to replace Bitcoin. Both serve different purpose. Ethereum was neither created to be a store of value nor as a currency for micro-transactions. ETH is used to fuel the dapps that run on it. Saying Ethereum will replace bitcoin is like saying a debt fund will replace equity fund, they are not even in the same category.
Bitcoin's biggest competitor is Dash & Monero. Both of these coins do everything Bitcoin does & more in a far better, faster and anonymous way.
The majority of the people don't look at what the technical aspects are of each crypto currency as they only pay attention to their highly inflated prices.
If Ethereum increases with let's say 100% in one month, where Bitcoin remains stagnant, Ethereum according to them is better, plus that its market cap is another indication that Bitcoin will get replaced.
It's a twisted way of thinking, but that's how things go here. People are blinded by their own greed and don't see what is really important to focus on. Market caps and pumps mean absolutely nothing.
Dash and Monero are doing their thing, but even these coins are no real competitor. They offer great anonymity features, but people are still using these coins for speculation purposes, and that's basically it.
