Ethereum or Litecoin would probably take the place of bitcoin. If bitcoin were to die tomorrow, it would probably drag down the altcoins with it as well, but if you give altcoins some time until they can establish themselves, they wouldn't be harmed in my opinion. An altcoin may eventually take the place of btc as the best crypto as well, especially considering the scalability issues that btc might face in the near future.
I don't think people will lost its interest to
BTCitcoin. Even if Ethereum and Litecoin starting to gain so much popularity now because of the price up,
BTCitcoin will still be on the mind of all people who do crypto business. They will never forget on how all started. They will still look and read any updates to what
BTCitcoin can bring. People will still be curious on how far
BTCitcoin will go up or will go down. Or what development of
BTCitcoin that will makes people invest more. As what I have said over and over again,
BTCitcoin will lead and altcoins will just follow.