What ever happens to bitcoin happens in all altcoins, bitcoin is the fundamental of all of them and the falling down of it might destroy their demand because investors will think that all of them might fail. Only investors decide for them if the investors deny them then there is no reason for it to still exist.
Indeed not the same system but bitcoin is the pioneer, that's why it will affect all altcoins. Because all altcoin value is still depend on btc for now. If btc down to 1$, i bet you all altcoin will be worth nothing. When the btc reach the max supply, i think that's the time the new "btc" will appear otherwise btc will still be the holygrail for cryptocurrency.