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.

do you mean this (BTC dead) will be going after then other crypto make be a first position in markets or before?
if BTC will be dead when he being in Top - cryptoindustry may be have a some problem..but for little period (maybe 1 year) - because now crypto tech is very fast upgoing and nobody cant stop him