Lets get your deduction from no facts out of the way, you dont actually know if there's an increasing number of people falling for scams, so your premise could actually be false. However, ignoring that part. It depends. This is the same question as why do people fall for scams at all. It is in human nature to want things for free. Scam sites often have deals that are 'too good to pass up', or in other words, literally 'too good to be true'. People are greedy. I mean there are places that just sell stuff and are fake, you buy the item and the site disappears. That isnt the person's fault. But I am very rarely going to feel bad for someone who has invested into a scam. If you look hard enough into it, the person has been told that they're going to earn lots of money in no time at all, and no risk. Seriously? on what planet has that ever been true? Answer to your question, people are greedy.
Scams are developing and changing. They're getting better at it the more they do it. Some sites tell you you'll get one thing, and you get something entirely different. You mention the young people specifically, the students? To be perfectly honest, our generations like to watch inappropriate things. And a lot of scams are originating on..."helping hand" sites. Listening to the radio a few mornings ago (I don't have choice of stations in the mornings, dangit), there was a story of a guy whose credit card bill just exploded with items that he never ordered, because he did once order a certain kind. The site was bugged: if you buy a single thing, it buys a lot more for you, and you never get any of it anyway.
Sites that look completely legitimate, aren't, and kids fall for that. Adults do too.
If someone has fallen victim to a scam website, chances are they didn't actually know the specific site was dangerous. Sure, everyone is warned to beware scammers but that doesn't do much in the way of identifying individual sites. It may be especially hard for someone to say no to someone if the person running the scam says something that resonates personally with the victim; I know of at least one instance that was reported in the news where a scammer was able to make their victim believe they were in love and she ended up forking over her entire savings account.
Short answer: naivety.
Yes, you are right and without knowing anything they might have been scammed again right? but still i came across some people who even after knowing some sties are scam , joined the same site spending so much time there and finally get disappointed to have wasted their valuable time and money