Yes, I think that's why prices fall after the ICO, because most of the projects that raised money, forget about the project and its promotion, advertising, that's all.
another side of this - if project got a lot of hype, there may be more people, who want to sell, than that, who want to buy. ICOs, nobody cries at every corner about, usually make more xxx than ovverhyped projects. Correct me, if im wrong.