Currently on the coinmarketcap site only about 1590 projects compared to at times more than 1700 projects. They have left many projects without developers or scam projects. I personally invested in some of these projects and lost a lot of money like bitconect and centra. Do you trust the projects you are investing in and will keep them for a long time until they succeed or are they just looking for profit in the short term?
That's why before invest on ICO you must find information about the project, the team, whitepaper, also the hype for the project. If the project is really good, their presale/private sale will sold out in a second. Luckly i never experience the scam on ICO.