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.

Only those alt coins will survive will have some unique features or benefits over bitcoins. However, in terms of price they will suffer as well. I do not excpet in anything except bitcoins currently.