If I am not mistaken, by the end of 2018 the ICO project has been abandoned by many parties for various reasons that have emerged and turned to the IEO.
ICO projects are still existing currently, not of them are abandoned by investors.
But only the ICO who really provide the information about their team, have a good marketing activity, etc.
IEO is the way ICO promote themselves on some trusted exchange, so the investors want to invest on it.