Altcoins are alive and well. This is only happening because bitcoin is forking and people want to get into the new currency and sell it as fast as possible to make some money. After that, the money will only flow back into altcoins and ethereum will go up. Ethereum is just an example, but altcoins all together will slowly take their position again.
Yes it will be alive this is into a correlation when bitcoin pump altcoin has dump its value. But, this is only the normal situation in the altcoins market. I agree, the case of hard fork event that is why altcoin are down but does not mean it is dying.