It might, sure, but it might also have to do with the fact that people carry almost nothing in cash compared to 40+ years ago.

In 1985, when I was a child, my father would care around $300 on him effectively at all times. Credit cards were still new, and checks were a limited option, most places you still needed cash. That's the equivalent of $850 today. I rarely carry more than $200 on my person today (less than the cost of a fancy dinner for two in San Francisco). The only reason I'm able to do that is because the vast majority of my transactions settle on a bank card.

You can argue that the change is surveillance, but the stark decrease in untraceable value I carry on my person is clearly an incentive for robbery that has been lost. It's also likely a major reason for the near-elimination of pick-pocketing in western society.