Bitcoin is still king of crypto and almost all of altcoin's price depend upon bitcoin's price so they will also fluctuate everytime when bitcoin moves a bit. Situation for altcoin get even worst when bitcoin will pump hard in very short time, people will jump back into bitcoin by selling their alts for bitcoin which will just make altcoin price to dump harder during bitcoin pump.
But not every alts get affected heavily during such pump, only few of alt might survive in future.
That is one crazy trend that we will keep seeing as time goes on which has even made me to start thinking of just abandoning alts at any slight chance I get now and concentrating more on just bitcoin to USDT trading since it seems to me to be more of a profitable way right now than having to worry so much about the value of some altcoins being affected by the bull run of bitcoin.
When we consider the core applications of cryptocurrencies then I doubt of most of the altcoins. If this is true then definitely bitcoin will kill maximum altcoins.