In my opinion, why bitcoin is superior to ethereum, because cryptocurrency is known as bitcoin, so bitcoin was first known and more popular than ethereum, but actually ethereum has advantages over currency.
Yeah, when someone knows crypto and he has introduced that to a newbie. That newbie probably have heard of cryptocurrencies and he's going to say that he knows bitcoin. It happens most of the time that the newbies get to know more bitcoin than any other altcoin.
But as per Ethereum, those that are into many altcoins. They might also be aware of ethereum as it's the first chain that has a lot of projects working on as erc20.
You’re right, people refer to cryptocurrency as Bitcoin because they have only seen and heard about Bitcoin, but that mindset is changing quite rapidly. With more people investing and trading cryptos these days, the whole world is getting to know about what Ethereum or Dogecoin, or Shiba Inu is. Everything takes time and the crypto world is no different.