According to my personal view, Why do people not believe in ICO. Not everyone who does not believe in ICO. There are still many who participate in ICO sales because participating in ICO sales will benefit if we invest in the ICO.
I believe the reason why they don't have faith in ICO is because they initially and generally thought it's not legit. They don't realize the benefit they can get from it if they only find time to learn and acquire needed information. On the other hand, maybe because of the negative news they heard and read. Different opinions are arising but the main goal here, either its legit or scam, is to think, inspect, and do research before making any decisions.