I think that altcoins usually reflect the price of Bitcoin. When Bitcoin is down then typically the altcoins are down. When Bitcoin is up then typically the altcoins are up. If Bitcoin collapses then all the altcoins will probably collapse as well. The only circumstance where I don't see this happening is if another cryptocurrency rises to the top and Bitcoin falls apart. That new cryptocurrency would act as the new benchmark for all the other cryptocurrencies. In this case, altcoins may be affected in the short term, but would continue on their way as if nothing happened.