That's the problem of most ICOs. They seem to be scams because they don't offer any prototype. Most of them look like a dream that needs money to be true. Really good projects offer prototype and clear roadmap and have to have some proofs of trust.
No real product = no chance to boom in the market and have a high chance to be scam stay away from that kind of ico project because you will lose your money.
Always look for a good ico project with a clear goal/roadmap provided.