So many ICOs. Surely not all of them are going to be successful. From this information we should learn that you have to investigate well before investing on any ICO.
Actually nowadays it is too difficult to find any good ICO. Even from "top" ICOs there are many scammers. I think the short pause would be not bad idea.
Well, maybe they were dead due to lack of care from the developer or the marketing team, some really after the sale don't have any plan with pumping of the price at all so it is really hard to invest nowadays.