there are so many icos in the market most of them are scam do you still belive in ico ?
Of course, I do trust ICOs. But definitely there will be failed projects even though the project teams will try to execute or as you said there can be scams as well.
Even if you look at startups, 90-95% startups fail within 5 years. So think it in the same way and try to figure out which 5-10% of projects will be successful.
Therefore, I suggest to do you due diligence, research the field as much as possible (the technology, its applicability, benefits of using blockchain vs. existing solutions, the team). If you do it correctly, you will be much more likely to find the successful projects.