$704K gross receipts in 4 months of work. Unless he was running a large call center, during that time I can't see where he would have had total expenses exceeding $100K. If he spent four months getting the whole thing set up and organized, he would have netted $600k in eight months, or about $900k, pre-tax. And he's probably not paying anywhere near full taxes on this.
And that is why these scams will continue. The unsophisticated operators - the ones who spent time in a call center working for someone else and who buy a list and just start making calls - can probably clear about $5k/month. The smarter ones, who know a bit more about how to do things, can make a lot more. And the really smart ones, the professional scammers, can take out $1 million per year, or more. There's a lot of money to be made without much work.
It seems to me that what does in most of these scammers is that they don't know when to quit. If they ran the scam for, say six months, then closed the doors and walked away, they would probably get away with it. But when they're bringing in a couple of hundred thousand per month, that's tough to do. So they keep it going, until they get caught.
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And then there are the truly great scammers, like the perps who ran the Belaire scam in Puerto Vallarta, where they keep the scam running for five years or more, and keep hitting up people several times over for more money.