It's simply greed that makes people fall to scam.
While greed is the major contributor to this successful scams, other factors have their role to play and this scammers are quite dedicated enough to keep trying untill they find someone that's lacking the knowledge general available on the internet like those just mentioned above.
The scammers have different techniques they use which is kind of hard to keep up with their tricks, to you as an informed individuals, the tricks aren't that hard to breakdown but as a newbie it'll be very difficult especially when they're not informed. The impersonation is very clean that if you don't look into this account more, you might just think you're speaking with the real users and end up trusting them.
The only way we can avoid falling for their tricks is to constantly look for new tricks this scammers are using and stay informed, also you have to put your greed to check and treat every contact you get on this social media platforms as scammers until proven otherwise.