I have a friend who's in jail for ~14 years now after hitting a third strike law with a fraud of ~ 30 million dollars.
Long story short, he did it because he was really good at it and got better over time. You don't knock something like this out without having done a lot of smaller stuff first, and by the time you get to this level of skill and sophistication, it's because it's easier to do this, and the skills you've built up don't apply well to real world jobs, or if they do at all, they don't pay nearly as much as you can get paid by running the scam, and with all that skill and experience, the risk of getting caught does go down quite a bit.
Long story short, he did it because he was really good at it and got better over time. You don't knock something like this out without having done a lot of smaller stuff first, and by the time you get to this level of skill and sophistication, it's because it's easier to do this, and the skills you've built up don't apply well to real world jobs, or if they do at all, they don't pay nearly as much as you can get paid by running the scam, and with all that skill and experience, the risk of getting caught does go down quite a bit.