First listing of a project is very importand IMO, if the price dumps the first week 90% for example, it is very difficult to drive the price back to ICO price, or above. That is why, a good exchange can be a "life saver", where there is enough volume. But that itself may not be enough, if the ICO do not have a good marketing plan after crowdsale, it is a big mistake, many ICO mainly focus only on collecting the money, and than kindof neglect the project, and the communication.