Just as when bitcoin hit $3200, many ICOs struggled and only some managed to stay alive healthy. And there were series of ICO tokensale extension and postponement. Now, BTC going down to $1000 will only make the situation worse and by then, majority of the ICOs will be pronounced dead.
I doubt that BTC will go down to $1000 again. If we will really see that price again, not only ICOs will have problems to raise money. Even a lot of already established crypto projects would probably have to shut down their operations in such a case.