Because making a $15,000 profit 5% of the time and nothing 95% of the time is better than making a $500 profit every time. Basically if scamming your customers

Because making a $15,000 profit 5% of the time and nothing 95% of the time is better than making a $500 profit every time. Basically if scamming your customers works a nontrivial fraction of the time and the margin when you're not scamming is small, scamming is the incentivized behavior.