The major causes after successful ICO is because of the investors that are invest huge amount during the pre sale and during ICO. After they have make their money and profit they have in focus they decided to dumped the token.
Discounts are evil. Bounty in tokens is evil as well. Both of them lead to a strong dump after the listing at any exchange. To prevent it founders should spend a lot of money to buy back tokens at the exchange with a high price. But there are too few teams which are able to do that.
this can only happen if project owners really trust their project and wants to see it develop. everybody is after the money now. some owners never really care much about the project they are working on. they all want to make gains and dump the project for another one. i think it acceptable for people that feel ICO should be abolished for one to focus on the available projects.