Altcoins are not one coin. They collectively are a continuum entity that is diverse and difficult to kill. Bitcoin is now the cathedral. The altcoins the barzar.
Or they are the small-scale cathedrals made of shity shiny plastic that some random guys try to sell you in front of real cathedrals. You decide to buy one and leave it happily on top of your fireplace, but its value only comes from the existence of the real cathedral.