Bitcoin is a very popular crypto coin today, we know that Bitcoin will be very expensive in the future but I imagine if Bitcoin die, whether there will be hope for the future of altcoin? because most altcoin exchanges are to bitcoins
your opinion is highly appreciated.

In my opinion, it'll never happen because all coins have differences and it will depend on the reasons why bitcoin died. If that happened, many people will lose their faith in other cryptos and it will have an impact but an only little. People will be affected if they didn't know how the market works. I believe ETH will take that place of BTC for being the no.1 cryptocurrency. We can't predict the market because everything is possible.