As most people seem to agree, one of the main factors is greed. So many of us want to get rich quick without putting in the time and effort, making ourselves easy targets for scammers. It gets a bit more complicated as the scammers are upping their game, spending more money to create a false sense of legitimacy to lure unsuspecting investors in. It really comes down to how people need to be ultra careful when they invest their money, far too many are willing to invest in a pipe dream; projects with no MVP, a poorly written white paper, lack of team information and more. Even a quick check on google will normally throw up some red flags, especially if you go more in depth on forums. I normally google the project name plus reviews, and that's just for starters. It's a jungle out there.