"Robbing banks: Crime does pay – but not very much," a paper by academic economists commissioned by the Royal Statistical Society and American Statistical Association on the economics of bank-robbery concluded that bank-robbers are wasting their time. The return from robberies is "rubbish". John Timmer summarizes the paper for Ars:
The basic problem is the average haul from a bank job: for the three-year period, it was only £20,330.50 (~$31,613). And it gets worse, as the average robbery involved 1.6 thieves. So the authors conclude, "The return on an average bank robbery is, frankly, rubbish. It is not unimaginable wealth. It is a very modest £12,706.60 per person per raid."
"Given that the average UK wage for those in full-time employment is around £26,000, it will give him a modest life-style for no more than 6 months," the authors note. If a robber keeps hitting banks at a rate sufficient to maintain that modest lifestyle, by a year and a half into their career, odds are better than not they'll have been caught. "As a profitable occupation, bank robbery leaves a lot to be desired."
Worse still, the success of a robbery was a bit like winning the lottery, as the standard deviation on the £20,330.50 was £53,510.20. That means some robbers did far better than average, but it also means that fully a third of robberies failed entirely.