Sometimes it happens that the new project does not receive enough financial support, they do not achieve ICO, IEO, IDO, STO, so it is normal for many to disappear.
But I have also seen that some manage to raise the funds but the team has NO experience or they are scammers and they simply disappear leaving investors losing.
I recommend that before investing you study the project well, mainly the team, that there is a great community supporting and good partners, this increases the level of success of a project.
there are also projects that were originally planned as a fraud mode, so that they made a lot of fakes, then disappeared after getting some funds from investors. sometimes fraudulent projects are also quite difficult to analyze, so if you do not have experience and knowledge, you should choose a project that is ranked at the top of d cmc.