Yes if bitcoin dies the altcoin will die indeed the concept of cryptocurrency will die. Because bitcoin is the trend setter it gave people a lot if it will be no more than there will be no crypto currency and no one will invest the new coin all have believe in it and this believe will make it live. 
Although it is very much difficult to say that if bitcoin will ever die. Because bitcoin is now becoming more and more stronger from time to time. But if unfortunately anything happen like that, then surely all altcoin coins will die, because bitcoin is the kind of all altcoins and it is not possible that without bitcoin any other currency will survive.