Many of them went bankrupt because they could not choose a good coin, many also bought only because they wanted a high increase regardless of the quality of the coins they bought, and when the market went down the coin coin would go down even further, ending in cut loss. So the suggestion is that I buy coins that have a clear project.
I think its not about choosing the good coin is responsible for their bankruptcy but entered the market at the wrong time, when the price was at its peak, I recalled during the bull runs most of the coins are very profitable a lot of ICOs investors made a lot of profits because there was a massive bull runs and a lot of investors came on board thus paved way for more ICOs into the system.