It depends. A lot of these scammers are extremely desperate. Some are forced into it. For others it's just an office job like any other.

Some firms actually do both legitimate support/customer service work and scamming side by side. I've called legit companies support lines before and the person picking up starts off doing some scam and them I'm like, "I thought this was Brand X," and they switch, "Oh yes, sorry about that. What was your order number?" That's how bad it's gotten.