Lots of reasons

• General cognitive decline

• Loneliness/isolation causes them to be more trusting of people who are nice to them

• Not keeping up with the latest information on scams can make them unaware of the scam they are falling for

• Financial desperation can lead them to turn a blind eye to something most people would be suspicious of.

• Once they have been scammed they can be too embarassed to let thier family know and so keep getting scammed