Most people that do this start small. He likely bought a small personal item on the company card and didn't get caught. Then he went bigger. Then he figured he could get away with even more and started falsifying receipts and documents. He got over confident and eventually got caught.
Most of these types of crimes don't start with doing thousands in theft the first month, they build up to it.
You've still got to be a scumbag though. Selling your integrity for $20 is actually worse than the $65k it eventually became for that guy.