With regards for your question if alt coins can survive if Bitcoin crash, will for me maybe a the short period of time some altcoins may survive but in the long run it can't. if Bitcoin the first crypto coin and the pillars of crypto currency die there is no reason altcoins where survive. they will all vanish one by one if ever bitcoin will be dead
Without bitcoin, it become extremely hard to manage other coins' survival on the exchange platforms. They probably all collapse to the floor and die.