That and the fact that people probably exaggerate the loss for insurance purposes.
Also, pickpockets and muggers are likely to profile their targets- Traditionally this would have been the wealthy, counterintuitively it's now the poor: People without credit cards and/or bank accounts, and immigrants paid in cash who are forced to walk or bike home from work through a bad neighborhood in the dark with an entire week's pay in their pocket.
$400 seems right. Jack someone's wallet and then walk into the nearest big box store to use their credit cards.
I've had my credit card # stolen 3 or 4 times and $400 is about the average amount of fraud that happened each time.
It's usually like a tank of gas and a trip to Best Buy to purchase something like a video game console. One time they bought a plane ticket online for $350.
I had someone steal my card info and use it to by a bed and mattress, which was delivered to their house.
Sears (ahem) wouldn't tell me who bought it, or where it was delivered, because I wasn't the purchaser, but they were happy to charge me for it. I turned it over to the police, but they said they weren't going to deal with it as it was 'only' ~$1200. This was in 2002 IIRC.
When such a thing happens, initiate a chargeback through your bank. Additionally federal (US) regulations limit your out of pocket expenses of fraud to $50.
I caught it about 2 days after it happened, and got the bank involved and had my money restored in a couple more days - that wasn't a big deal. The frustrating thing was that this was just 100% glossed over by law enforcement. This wasn't a $40 meal splurge by a petty thief - it was a freakin bedroom set.
They weren't to know - I might have bought a bed and shipped it to someone in another state as a gift. After I told them it wasn't my purchase, however, they should have given me the info, but they didn't. Police didn't seem to care, bank didn't seem to care. Odd...
That's over $400 per incident. Either people carry a hell of a lot of cash on them or there are some outliers with some interesting stories to tell.