Very soon, I think. The cash just dissapiar from our life in next 15-25 years. The humanity just change cash and will use only other pay systems.
Lol. Did you imagine if the cash will disappear? I don't even think about it, because it's impossible to stop using cash. It's part of our life there's a lot of poor people in the world, the others are don't have a gadget or don't know how to used it, even a card.