Ooh we're still the capital of something.
Personally I think this comes down to ineffective education in many cases. Yes, some of these scams are getting quite impressively advanced, and they tend to target older people who are declining in cognitive ability, but so often the victims are absolutely unwilling to admit they were a bit stupid. It's always someone else's fault, like the bank, or the police, or Facebook, and not theirs for doing a direct bank transfer to some random person who told them it was an emergency. It is frustratingly hard to protect old people from this though - my nan got scammed for a new mattress by a door-to-door salesman when she was in a care home, who dropped the ball by letting him in at all. Another OAP I know would be a fairly easy target too, as she seems like she'd trust a "nice young man" more than her own family at this point (unwarranted, I should add).
Our tech education in particular was fucking woeful when I was at school and I have to assume it's little better now. To me, avoiding scams seems fairly straightforward:
1) If it's too good to be true, it's not true.
2) Never fill out a form from a link in an email.
3) Don't provide any details to anyone who phones or emails you, always look up their official phone number and phone them back. I use multiple devices to do this and multiple sources to avoid compromised sites like one of the examples. Call up the directory service on the phone and compare that too, if needed.
Perhaps there's also a cultural aspect to why the British are so easy to scam? Maybe our curious mix of laziness, stupidity, superiority complex, and greed combine to make us the perfect targets.