In my opinion. Main reasons are low quantity of very successful ICOs, and not too much positive news.
ICOs ? it's a cancer in cryptosphere mate.
as we can see,many people started to join the community after they heard the ads on internet about 'something' related to cryptocurrency and technology such as those ICOs.
they felt intrested and started to join,
but when the project concluded the sale,they're gone forever.
that was why many people do not want to invest or join or whatever you called it their money or time into cryptosphere.
every bad news that we heard was related to Fraud and Fake ICOs,nothing great came from those shitty ICOs i believe.