Could destroy Bitcoin. But another cryptocoin could emerge and the easiest way to get this new coin would still be by using Bitcoin.
I do not think this could destroy bitcoin however if it had a big impact, I will bet that most alts will get affected too, all the coins are priced on bitcoin, if you want to get alts you need to get bitcoin first, if people began to get rid of their bitcoin because of a collapse then the same will happen to other alts, I think the fate of all alts is linked to bitcoin, if bitcoin fails then everything fails.