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.

Bitcoin operates on one separate blockchain which other altcoins utilize as well. There are other blockchains such as the ETH one which has erc20 tokens that many altcoins utilize. Also, theres the waves competitor as well. Bitcoin has its own ecological environment though so do its competitors.