I personally do not believe this statistics that 99% of ICOs are scam, because some ICOs fail do not mean they are all scam. I usually tell people that starting an ICO is like starting a new business, it might succeed immediately, it might fail presently but have a great future and it might fail totally beyond redemption. So because a project is failing to perform presently or fail totally do not mean it is a scam. Don't get me wrong here, I never said there are no scam projects but the rate is not as high as alleged. Judging a project based on its first few years is wrong, give it time to realize its potentials.
I partially agree with your statement, ICOs are business that has 50% chance of success and the ratio of success will increase if the team work hard on their goals. There are still small projects that dump after listing but the team keeps delivering on their product and that is not a scam but if the team stops on developing then we can call it a scam.