ICO's are getting really low on popularity because they are doing IEO's now. As exchanges progress too, projects who wants to be known are launching their projects on it and giving more security to the investors who will possibly buy their tokens.
The popularity of ieos is not going to last long, at the beginning people got excited over them because they saw them as a better alternative to icos and in a way they are, but as long as the projects keep losing money in the long term and are unable to fulfil their goals then there is not going to be any way in which exchanges can sustain the popularity of those coins, people do not have an infinite amount of money to lose and even if they do not lose everything they will stay away from ieos from that moment on.