No I don't actually agree with this. The fact that ETH's price is kind of stable than that of Btc doesn't invoke ETH as the new boss of cryptocurrencies. Statistical records still shows a huge gap in the prices, popularity and usage if we are to compare and contrast both coins. However, I am putting away the possibility of that happening, but not anytime soon. ETH still gat a long to go reach Btc's level and eventually conquer it as the new king in the Cryptos world. Even after this feat has been achieved, Btc will still go down in history as the pioneering coin of the entire cryptosystem.
I also think it is an undeniable fact that while Ethereum prices may overtake bitcoin in the years ahead, it is undeniable that bitcoin is the first coin in the entire crypto-cryptocurrency world. Unless there are some big surprises in Bitcoin, Ethereum may replace it with bitcoin.