Its already 2019 and I am not sure why there are still people falling for this kind of scam. Its pretty obvious on the first glance, you should know almost in an instant if the site is just scam or not. Promising fixed returns after XX number of days is red flag.
People really have no clue, and there is some form of a believe that the next time will be different, while that's obviously not the case at all--if things look too good to be true, they mostly are.
If you also add that people totally not familiar with what's normal and what isn't join the space on a daily basis, you'll understand that there is a constantly flow of potential victims these con artists aim to bank on.
People still fall for blatant email phising scams where they click on a link, fill in their personal details and send their bank card to whatever unknown address. It's retarded if you think about it, but it still happens today.