Indeed, there are many who invest in projects whose sources are unclear, and in the end they do scams. But now investors are more familiar with which projects are really serious about running their business, and which ones will commit scams. If you see in 2017 there are also many project scams. But nothing details. I think investors are now smart.
Losses due to fraud do exist in all fields, not just cryptocurrency. That is why we have to do an in-depth analysis to minimize the risk. Knowledge and experience, as you explained, are very necessary as a fortress of fraudsters who are increasingly smart to take advantage of opportunities and cover up their ugliness. My advice, never invest money that you can't afford to lose.