Technology will continue to have a material impact on the amount of cash in circulation, of course. The evolution of money is fascinating to watch, though I believe it is important to consider that not everyone will be able to participate in this fantasy we dream of.

Open-loop prepaid cards have helped eliminate paper transfer channels to a degree (which is a positive step in the right direction) but we cannot ignore the 2.5B people on this planet who do not have access to modern financial services at all. For the rural farmer in Southeast Asia, cash is all he/she knows.