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.

The reason why altcoins are created is to compete with bitcoins and because of that, there's a huge chain reaction that happened in the market, the competition become even tighter and the good outcome is that, bitcoins value is increasing further more so expect the bright future for cryptocurrency in the market and invest today.
Honestly, at current, Altcoin is just a factor to increases the price of Bitcoin. Do you know any altcoin can against the bearish of Bitcoin in past weeks? The value of Bitcoin dumped to $6,000 also made a lot of altcoins dumped 30-50% within one day, example NEO from $120 dumped to $60 and bounce to old price just within 48 hours.