Because there were too much of them in 2017. Good projects are already made, junk only left (except some, but they are rare). So, there are less chances to get even a soft cup. Thus ICOs will be less popular in 2018.
Yes, you are right with this. I agree with you because there are too many of them in 2017 so the ICO in 2018 is less popular and sometimes there is fraud. 