Some theft is efficient. If a hypothetical thief grabs a few bills from an unattended wallet, and the wallet's owner wasn't counting on having a specific amount of money available soon after, the amount lost by the victim is roughly equal to the amount gained by the thief.
Stealing copper from power lines and transformers is among the least-efficient kinds theft; it's hard to do worse without shooting a wealthy philanthropist couple to steal a wallet and a pearl necklace. I have seen a term suggested--the "rapacity index"--for the ratio of value gained by the thief, to value lost by the victim. I think it makes sense to take a crime's rapacity index into consideration during sentencing.
That ignores higher order effects--how theft changes primary behavior. In your example, fear of pick pocketing may reduce the degree to which people carry around and spend money with vendors. Your rapacity index makes little sense: by your logic, corruption has a low rapacity index, since the state has a lot of money compared to the amount of the transaction. And given the deterrent function of sentencing, the more relevant figure is the aggregate effect of a particular class of theft, not an individual instance of theft.
> fear of pick pocketing may reduce the degree to which people carry around and spend money with vendors.
Yes, that's why I specified an unattended wallet. I agree that direct monetary loss is not the total harm to the victim.
> corruption has a low rapacity index, since the state has a lot of money compared to the amount of the transaction.
That's not the calculation I suggested. Corruption isn't always the same as theft--and, if it were decided so, the calculation for corruption would be the money absconded with by the taker, divided by the money lost by the victim. In many cases of corruption, as in power line theft, the victim is diffuse; it's usually harder to calculate exact numbers, but this kind of calculation is done in court all the time.
Stealing copper from power lines and transformers is among the least-efficient kinds theft; it's hard to do worse without shooting a wealthy philanthropist couple to steal a wallet and a pearl necklace. I have seen a term suggested--the "rapacity index"--for the ratio of value gained by the thief, to value lost by the victim. I think it makes sense to take a crime's rapacity index into consideration during sentencing.