I also thining about it sometimes... I think that people scam mainly because of easy money. They only want to earn huge money with the low cost of money and energy. Crypto world is even easier way for them to do this because of more anonymity, decentralization and you know.
They also scam because of discontentment. They are not contented with waht they have that they are willing to do harm to other peopls for the sake of money. Yes your right, cryptocurrecies provide anonymity for the users that is why it is very vulnerable for theft attack and scam. It's very risky to transact with other people.