IMO, it is not only the prices of ICO projects coins are shrinking. The overall crypto market has been affected. If you believe in the project, it is a good time to buy more of the coin at a low price.
We can't pin point at what really the cause of this downfall. I have seen successful ICOs which the value of it's token remain the same or even surpasses it's ICO price but there are speculations that these were manipulated while most of the token really goes down along with bitcoin.