Altcoins will not die if bitcoin reach that high price, the market will grow for sure the prices of cryptos will also increase, and I think only shit coins or useless coins will surely die.
As seen in 2017 yesterday, where the price of bitcoin surged, altcoin price even followed. I think everything is appropriate, where the useful altcoins will continue to live and the useless ones will always die even though the bitcoin price is exorbitant.