I wonder how much of the drop is due to simply having less physical cash lying around to steal, as most economic transactions move to electronic payment methods

I wonder how much of the drop is due to simply having less physical cash lying around to steal, as most economic transactions move to electronic payment methods. I know pickpocketing has fallen off as lack of cash means thieves end up with quickly cancelled credit cards and hard to pawn smartphones instead of untraceable cash. Obviously banks still need to keep some cash on hand, but I'd think that most smaller banks (which are presumably the easier ones to rob) would've abandoned keeping the classic "giant vault with stacks of cash". (the article brings this up briefly, but doesn't really quantify it). And as the number of places that do have big piles of cash decreases, the amount of resources that can be put into protecting each one increases, so you'd expect the difficulty of robbing them to increase faster then linerally with decreasing numbers sites.